Optical member and method for producing the same

Abstract

To provide an optical member capable of arbitrarily controlling reflectance, excellent in film strength and having small wavelength dependence of reflectance.SOLUTION: An optical member 101 includes a body 1 and an optical functional layer 20 containing particles and having a uniform thickness on the body 1, in which when the optical functional layer 20 is divided into a plurality of layer regions 21 to 27 by dividing the optical functional layer 20 for each 100nm in a thickness direction of the optical functional layer 20 from an interface between the body 1 and the optical functional layer 20, a difference between refractive indices of at least one pair of adjacent layer regions is more than 0 and 0.1 or less.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to an optical member and a method for manufacturing the same. [Background technology]

[0002] Conventionally, the surfaces of optical lenses and displays are provided with coatings whose refractive index is adjusted to suit the application.

[0003] For example, Patent Document 1 proposes a method for manufacturing an optical element having an antireflection film with a gradient refractive index structure layer whose refractive index gradually increases toward the transparent substrate in the thickness direction, and an interference layer disposed between the gradient refractive index structure layer and the transparent substrate to suppress reflected light by interference action, with the aim of manufacturing an antireflection film with a gradient refractive index film that is highly productive and has excellent antireflection properties (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an optical member that can arbitrarily control the reflectance, has excellent film strength, and exhibits small wavelength dependency of the reflectance. [Means for solving the problem]

[0005] The optical element of the present invention as a means for solving the problem is an optical element having a base and an optical functional layer on the base, the optical functional layer containing particles and having a uniform thickness, wherein when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the base and the optical functional layer in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide an optical member which can arbitrarily control the reflectance, has excellent film strength, and exhibits small wavelength dependency of the reflectance. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is a schematic cross-sectional view showing an optical member according to one embodiment of the present invention. [Figure 1B] FIG. 1B is a schematic cross-sectional view showing an optical member according to another embodiment of the present invention. [Figure 2A] FIG. 2A is a schematic cross-sectional view showing an optical member according to another embodiment of the present invention. [Figure 2B] FIG. 2B is a schematic enlarged view of the interface between adjacent layer regions in the optically functional layer of FIG. 2A. [Figure 3A] FIG. 3A is a schematic top view showing an example of the state when droplets of a liquid composition for one scan land in a film formation step of a manufacturing method for an optical component according to one embodiment of the present invention. [Figure 3B] Figure 3B is a schematic top view showing another example of the state when droplets of a liquid composition for one scan land when forming a printing pattern in the film formation process of a method for manufacturing an optical component according to one embodiment of the present invention. [Figure 4A] FIG. 4A is a schematic cross-sectional view showing a state after an optical functional layer forming step in a method for producing an optical member according to one embodiment of the present invention. [Figure 4B] FIG. 4B is a schematic top view showing a printing pattern for forming each layer in FIG. 4A. [Figure 5A] Figure 5A is a schematic side view showing the process of ejecting droplets of low refractive index liquid composition 41 from a second inkjet head onto an optical functional layer formed of droplets of high refractive index liquid composition 42 in a 100% cured state ejected from a first inkjet head and curing the droplets. [Figure 5B] Figure 5B is a schematic side view showing the process of ejecting droplets of low refractive index liquid composition 41 from a second inkjet head onto an optical functional layer made of droplets of high refractive index liquid composition 42 in a 50% cured state ejected from a first inkjet head and curing the droplets. [Figure 6A]FIG. 6A is a schematic side view showing a process of discharging droplets of a low refractive index liquid composition 41 for a second layer onto a first optical functional layer that is in a 100% cured state, and curing the droplets. [Figure 6B] FIG. 6B is a schematic side view showing a process of discharging droplets of a low refractive index liquid composition 41 for a second layer onto a first optical functional layer that is in a 50% cured state, and curing the droplets. [Figure 7] FIG. 7 is a schematic diagram showing the discharge data in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0008] The optical member provided with the antireflection coating described in Patent Document 1 has concerns about wavelength dependency of reflectance due to discontinuity in the refractive index between the refractive index gradient structure layer and the interference layer. Furthermore, the reflectance may be as low as about 1% depending on the wavelength range, leaving room for improvement. Furthermore, optical members having a moth-eye structure with minute concave-convex structures have been widely used in the past, but the durability of the moth-eye structure leaves room for improvement.

[0009] The optical member of the present invention can fully resolve various concerns in the prior art. More specifically, it is possible to realize an optical member in which the reflectance can be controlled arbitrarily and the wavelength dependency of the reflectance is small. Furthermore, the optical member also has excellent film strength, which is a basic performance.

[0010] The present invention will be described in detail below.

[0011] (Optical components) The optical member of the first aspect of the present invention has a substrate, an optically functional layer containing particles on the substrate and having a uniform thickness, and may have other layers or portions as necessary.

[0012] <Base> The substrate is not particularly limited and can be appropriately selected depending on the purpose, but is preferably transparent.Specific examples include cellulose acylate films (e.g., cellulose triacetate films, cellulose diacetate films, cellulose acetate butyrate films, cellulose acetate propionate films), polyethylene terephthalate films, polyethersulfone films, polyacrylic resin films, polyurethane resin films, polyester films, polycarbonate films, polysulfone films, polyether films, polymethylpentene films, polyether ketone films, cycloolefin polymers, (meth)acrylonitrile films, polyolefins, polymers having an alicyclic structure (e.g., norbornene resins), and transparent glass.

[0013] The refractive index of the substrate is not particularly limited, but is preferably 1.40 to 1.75, more preferably 1.45 to 1.70. By setting the refractive index of the substrate to 1.40 to 1.75, the difference in refractive index between the substrate and the optical functional layer can be set within a preferred range.

[0014] The method for measuring the refractive index of the substrate is not particularly limited and can be appropriately selected depending on the purpose. For example, the measurement can be performed using a spectroscopic ellipsometer M-2000 (manufactured by JA Woollam Japan) or a spectrophotometer (V-770, manufactured by JASCO Corporation).

[0015] The average thickness of the substrate is not particularly limited and can be set appropriately depending on the purpose, but from the viewpoint of increasing transmittance, it is preferably 25 μm or more and 1,000 μm or less, more preferably 25 μm or more and 250 μm or less, and even more preferably 30 μm or more and 90 μm or less.

[0016] The method for measuring the thickness of the substrate is not particularly limited and can be appropriately selected depending on the purpose, and can be measured by physical or optical techniques such as a stylus-type step film thickness meter (Alpha-Step D-500, manufactured by ULVAC) or an optical interference film thickness meter (heliInspect, manufactured by Heliotis), or by cross-sectional observation using a heated cathode field-effect scanning electron microscope (Schottky FE-SEM).In this specification, the average thickness of the substrate is defined as the average value of thicknesses at three arbitrarily selected points on the substrate 1.

[0017] The width, size and shape of the substrate are not particularly limited and can be appropriately set depending on the application of the optical member.

[0018] When the substrate has a structure in which the refractive index changes in the thickness direction of the substrate, when the substrate is divided into a plurality of substrate layer regions at intervals of 100 nm or less from the bottom surface of the substrate in the thickness direction of the substrate, the refractive index difference between at least one pair of adjacent substrate layer regions is preferably greater than 0 and less than 0.1. By configuring the substrate in this way, it is possible to further increase the transmittance and further reduce wavelength dependency. Note that when the total thickness of the substrate is less than 200 nm, the refractive index difference can be determined by dividing it into two equal parts.

[0019] In this specification, the "direction intersecting the thickness direction of the substrate" preferably means a direction perpendicular to the thickness direction of the substrate, that is, a planar direction of the surface of the substrate.

[0020] The bottom surface of the substrate means the surface opposite the interface between the substrate and the optical functional layer when the optical functional layer is disposed on only one surface of the substrate, and means any selected surface of the substrate when the optical functional layer is disposed on both surfaces of the substrate.

[0021] The method for measuring the refractive index difference between each substrate layer region in the substrate is the same as the method for measuring the refractive index difference between each layer region in the optical function layer.

[0022] <Optical functional layer> The optically functional layer is disposed on the substrate, contains particles, and has a layer shape with a uniform thickness.

[0023] When the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the difference in refractive index between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. Here, the layer region refers to each region when the optical functional layer is divided into a plurality of layers in the thickness direction of the optical functional layer.

[0024] In this specification, "having a uniform thickness" means that the undulations are 80 nm or less. The undulations refer to an uneven structure having alternating concave and convex portions on the surface. Such an uneven structure is generally called a moth-eye structure. The uniform thickness of the optical functional layer preferably has an undulation of 60 nm or less, more preferably 40 nm or less.

[0025] In this specification, the "thickness direction of the optical functional layer" includes the direction from the interface between the substrate and the optical functional layer toward the substrate (hereinafter sometimes referred to as the "-thickness direction of the optical functional layer") and the direction from the interface between the substrate and the optical functional layer toward the exposed surface of the optical functional layer (hereinafter sometimes referred to as the "+thickness direction of the optical functional layer"); however, when the optical functional layer is divided into multiple layer regions, it means the +thickness direction of the optical functional layer.

[0026] It is preferable that each layer region has an optical thickness within the range of the following formula, since this makes it easier to obtain a low reflection effect: In the formula, λ is the wavelength of light at which reflection is prevented by the optical member of the present invention. Optical thickness (nd) = λ / 4

[0027] Therefore, when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. If the total thickness of the optical functional layer is less than 200 nm, the refractive index difference can be determined by dividing the optical functional layer equally into two.

[0028] The refractive index of the optical functional layer does not necessarily have to change continuously; adjacent layer regions may have layer regions with no change in refractive index. In other words, as long as the difference in refractive index between at least one pair of adjacent layer regions among the plurality of layer regions is greater than 0 and less than 0.1, the difference in refractive index between one layer region and another layer region adjacent to the one layer region may be zero. For example, if the optical functional layer is divided into three layer regions, the difference in refractive index between the first layer region and the second layer region may be greater than 0 and less than 0.1, and the difference in refractive index between the second layer region and the third layer region may be zero. The same applies when the optical functional layer is divided into four layer regions. That is, as long as the difference in refractive index between at least one pair of adjacent layer regions among the plurality of layer regions is greater than 0 and less than 0.1, the plurality of layer regions in the optical functional layer may include one or more layer regions with a refractive index difference of zero.

[0029] Furthermore, the difference between the maximum and minimum values ​​of the refractive index of the optical functional layer is preferably 0.2 or more from the viewpoint of improving the low reflection effect when the optical member is controlled to have a low reflectance, and is preferably 0.4 or more from the viewpoint of improving the high reflection effect when the optical member is controlled to have a high reflectance.

[0030] The difference in refractive index between the substrate and the layer region of the optical functional layer in contact with the substrate is preferably 0.1 or less.

[0031] As will be explained later in the manufacturing method of an optical component, the optical functional layer can be suitably formed by repeating the film formation step and the film curing step multiple times. Therefore, the optical functional layer has a laminated structure. The refractive index difference between the multiple layer regions in the optical functional layer is formed due to the manufacturing method of the optical component.

[0032] By setting the difference in refractive index between at least one pair of adjacent layer regions in the optical functional layer to be greater than 0 and not greater than 0.1, it is possible to gradually change the refractive index from the layer region in contact with the substrate to the outermost layer region of the optical functional layer, thereby suppressing the influence of interfacial reflection between each layer region. In other words, the optical member of the present invention can exhibit the optical function of a moth-eye structure without having a moth-eye structure, and is excellent in film strength such as adhesion and scratch resistance.

[0033] When the optical member of the present invention is used to impart a light-collecting function, a function of eliminating unnecessary light, or the like to window glass, a solar panel, or the like, and when the substrate is a lens, the substrate may have a structure in which the refractive index changes in the thickness direction of the substrate, similar to the optical functional layer. Examples of the lens include a glass lens and a plastic lens made of a cycloolefin polymer or polycarbonate.

[0034] The method for measuring the refractive index difference between each layer region in the optical functional layer is not particularly limited and can be appropriately selected depending on the purpose, and can be measured using, for example, a spectroscopic ellipsometer M-2000 (manufactured by JA Woollam Japan), a spectrophotometer (V-770, manufactured by JASCO Corporation), etc. Specific examples of the measurement method are as follows.

[0035] First, the total film thickness is calculated using physical and optical techniques such as a stylus-type step film thickness meter (Alpha-Step D-500, ULVAC) and an optical interference film thickness meter (heliInspect, Heliotis), as well as cross-sectional observation using a Schottky FE-SEM. The refractive index of the entire optical functional layer is measured using a spectroscopic ellipsometer M-2000 or a spectrophotometer, and the total film thickness is entered during analysis. Analysis data is obtained with the total film thickness on the horizontal axis and the refractive index distribution on the vertical axis, and the refractive index difference between each layer region is calculated.

[0036] When the optical functional layer contains particles, the refractive index difference between each layer region in the optical functional layer can also be measured by the following method. First, a two-dimensional cross-section is observed using a heated cathode field-effect scanning electron microscope (Schottky FE-SEM), or a sample is processed and exposed using a focused ion beam device, and a three-dimensional cross-section is observed using a scanning electron microscope (Carl ZEISS (SII-NT), FIB / SEM crossbeam device NVision 40). From the image data obtained, the particle amount ratio from the outermost layer to the layer closest to the substrate is calculated by image processing. Next, three types of films with different particle ratios are prepared and measured using a spectroscopic ellipsometer M-2000 or a spectrophotometer. From the data, the relationship between the particle concentration ratio and the refractive index is calculated, and the refractive index is estimated from the particle ratio obtained previously. The refractive index difference between each layer region in the optical functional layer is calculated from the calculated refractive index.

[0037] The average thickness of the optical functional layer in the present invention is not particularly limited and can be appropriately selected depending on the desired optical function. From the viewpoint of improving productivity and transmittance, however, it is preferably 10 nm or more and 100 μm or less, more preferably 20 nm or more and 10 μm or less, even more preferably 30 nm or more and 1 μm or less, and particularly preferably 50 nm or more and 500 nm or less.

[0038] The method for measuring the thickness of the optical functional layer is not particularly limited and can be appropriately selected depending on the purpose, and can be measured using, for example, physical or optical techniques such as a stylus-type step film thickness meter (Alpha-Step D-500, manufactured by ULVAC) or an optical interference film thickness meter (heliInspect, manufactured by Heliotis), or cross-sectional observation of the film using a heated cathode field-effect scanning electron microscope (Schottky FE-SEM).In this specification, the average thickness of the optical functional layer is defined as the average value of thicknesses at three arbitrarily selected points on the optical functional layer.

[0039] The refractive index of each layer region of the optical functional layer is not particularly limited, but is preferably 1.0 to 2.5, and more preferably 1.2 to 2.0. If the refractive index of each layer region of the optical functional layer is 1.0 or more, it is less likely that an additional process (sol-gel method, etc.) will be required during the production of the optical component in order to achieve that refractive index. If the refractive index of the optical functional layer is 2.5 or less, the optical component can be easily produced and the transparency of the optical component can be maintained.

[0040] The method for measuring the refractive index of the optical functional layer is not particularly limited and can be appropriately selected depending on the purpose. For example, the refractive index can be measured using a spectroscopic ellipsometer M-2000 (manufactured by JA Woollam Japan) or a spectrophotometer (V-770, manufactured by JASCO Corporation).

[0041] The optical functional layer of the optical member of the present invention can be formed by applying a liquid composition onto a substrate. As the liquid composition, those described in the section (Method for producing an optical member) below can be suitably used.

[0042] <<Particle>> The optical functional layer may contain one type of particle or two or more types. The optical functional layer may have a layer region that does not contain particles, but it is preferable that all layer regions contain particles, and it is more preferable that the outermost layer region of the optical functional layer contains particles. The outermost layer region of the optical functional layer refers to the layer region on the surface of the optical functional layer opposite the surface of the optical functional layer that contacts the substrate in the thickness direction of the optical functional layer. It is more preferable that the particles are exposed on the outermost surface of the optical functional layer. By adopting these preferable configurations, the refractive index of the surface of the optical component can be further reduced.

[0043] The particle content of the optical functional layer preferably varies along the thickness direction of the optical functional layer, and more preferably increases or decreases from the layer region in contact with the substrate toward the outermost layer of the optical functional layer.

[0044] When the optical functional layer contains at least two types of particles, it is preferable that the total content ratio of the at least two types of particles varies along the thickness direction of the optical functional layer, and more preferably, the total content ratio of the at least two types of particles increases or decreases from the layer region in contact with the substrate toward the layer region of the outermost layer of the optical functional layer.

[0045] For example, when the optical functional layer contains one type of particle, it is preferable that the particle content ratios in a pair of adjacent layer regions of the optical functional layer are different from each other.

[0046] For example, when the optical functional layer contains at least two types of particles with different refractive indexes, it is preferable that the content ratios of the at least two types of particles with different refractive indexes in a pair of adjacent layer regions in the optical functional layer are different from each other. Here, the content ratio of the at least two types of particles with different refractive indexes may be 0 for one of the particles. When the optical functional layer contains at least two types of particles with different refractive indexes, it is more preferable that each of the pair of adjacent layer regions contains particles with different refractive indexes.

[0047] For example, when the optical functional layer contains at least two types of particles with different refractive indices, it is preferable that the content ratio of other particles with a refractive index different from that of one particle relative to the content ratio of one particle in the optical functional layer increases or decreases from the layer region in contact with the base toward the layer region of the outermost layer of the optical functional layer.

[0048] The method for measuring the refractive index of particles is not particularly limited and can be appropriately selected depending on the purpose. For example, the measurement can be performed using an Abbemat MW (manufactured by Anton Paar) or an Abbe refractometer (manufactured by Atago Co., Ltd.).

[0049] When the optical functional layer contains at least two types of particles, it is preferable that the particles contain at least two types of particles with different refractive indices. The at least two types of particles with different refractive indices preferably contain low-refractive-index particles with a refractive index of less than 1.5 and high-refractive-index particles with a refractive index of 1.5 or more.

[0050] For example, when the optical functional layer contains two types of particles with different refractive indices, the particles with a relatively low refractive index are referred to as "low-refractive-index particles," and the particles with a relatively high refractive index are referred to as "high-refractive-index particles." When the optical functional layer contains at least three types of particles with different refractive indices, the particles with the highest refractive index are referred to as "high-refractive-index particles," and the particles with the lowest refractive index are referred to as "low-refractive-index particles."

[0051] When high-refractive-index particles and low-refractive-index particles are mixed in an optical functional layer, increasing the content of high-refractive-index particles in one optical functional layer increases the refractive index of the optical functional layer, while increasing the content of low-refractive-index particles in one optical functional layer decreases the refractive index of the optical functional layer.

[0052] -Low refractive index particles- The refractive index of low refractive index particles is less than 1.5. There are no particular limitations on the low refractive index particles, and they can be appropriately selected depending on the purpose as long as they have a refractive index of less than 1.5. Examples of low refractive index particles include polymer particles, silica particles, oxide particles, and particles that form voids inside when exposed to external energy.

[0053] The polymer in the polymer particles is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include crosslinked acrylic.

[0054] The oxide in the oxide particles is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include zirconia and titanium oxide.

[0055] The structure of the low refractive index particles is not particularly limited and can be appropriately selected depending on the purpose, and may have, for example, a hollow structure or a porous structure. The porosity of the low refractive index particles having a hollow structure or a porous structure is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 40% or more and 80% or less from the viewpoint of lowering the refractive index of the optical functional layer and increasing the durability of the low refractive index particles themselves.

[0056] The method for measuring the porosity of low refractive index particles is not particularly limited and can be appropriately selected depending on the purpose. For example, the porosity can be measured using a Poremaster (Anton Paar) by mercury intrusion porosimetry, a gas adsorption specific surface area / pore size distribution analyzer (manufactured by Seika Digital Image Co., Ltd.) by gas adsorption, or by examining the relationship between the apparent density D1 and true density D0 of the particles.

[0057] An example of how to estimate the porosity of a particle based on the relationship between the apparent density D1 and the true density D0 of the particle is described below. First, let us consider a volume of 100 cm 3 30cm into a measuring flask 3 The particles are packed into the volumetric flask, and the mass of the packed particles is accurately weighed. Next, the volumetric flask filled with the particles is accurately filled up to the marked line with isopropanol, taking care not to introduce air bubbles. The mass of the isopropanol added to the volumetric flask is accurately weighed, and the apparent density D1 (g / cm) of the particles is calculated based on the following formula (I): 3 ) is calculated.

[0058] (Number 1) Apparent density D1 (g / cm 3 ) = [particle mass] / (100 - [mass of isopropanol] ÷ [specific gravity of isopropanol at the measurement temperature]) Equation (I)

[0059] Next, a capacity of 100 cm 3 Approximately 10 g of crushed particles are filled into a measuring flask, and the mass of the crushed pieces is accurately weighed. In the same manner as in the measurement of apparent density D1, isopropanol is added to the measuring flask, and the mass of the isopropanol is accurately weighed. The true density D0 (g / cm) of the particles is calculated based on the following formula (II): 3 ) is calculated. Note that when calculating the true density D0, voids are not considered to be part of the particle.

[0060] (Number 2) True density D0(g / cm 3 ) = [mass of crushed particles] / (100 - [mass of isopropanol] ÷ [specific gravity of isopropanol at the measurement temperature]) Equation (II)

[0061] The porosity (%) of a particle is calculated from the apparent density D1 and true density D0 of the particle by the following formula (III).

[0062] (Number 3) Porosity (%) = 100 - (apparent density D1 / true density D0) × 100 Equation (III)

[0063] The shape of the low refractive index particles is not particularly limited and can be appropriately selected depending on the purpose, and may be, for example, regular or irregular. Examples of regular low refractive index particles include spherical, plate-like, flaky, rod-like, columnar, needle-like, dendritic, spongy, angular, and elliptical shapes.

[0064] The size of the low refractive index particles is not particularly limited and can be appropriately selected depending on the purpose, but the average primary particle diameter is preferably 1 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less. For example, from the viewpoint of excellent haze reduction effect, the average primary particle diameter of the low refractive index particles is preferably 100 nm or less. The particle size may be appropriately adjusted depending on the application.

[0065] The method for measuring the particle size of low refractive index particles is not particularly limited and can be appropriately selected depending on the purpose. For example, the particle size can be measured using a particle size distribution analyzer using a dynamic light scattering method (VASCO, manufactured by CORDUAN), a laser diffraction particle size distribution analyzer (Partica LA-960V2, manufactured by HORIBA, Ltd.), or by cross-sectional observation using a heated cathode field-effect scanning electron microscope (Schottky FE-SEM).

[0066] -High refractive index particles- The high-refractive-index particles have a refractive index of 1.5 or more. The high-refractive-index particles are not particularly limited and can be appropriately selected depending on the purpose as long as they have a refractive index of 1.5 or more. For example, oxide particles containing at least one selected from aluminum, zirconium, titanium, zinc, germanium, indium, tin, antimony, and cerium are preferred.

[0067] The structure of the high refractive index particles is not particularly limited and can be appropriately selected depending on the purpose, and may have, for example, a hollow structure or a porous structure. The porosity of the high refractive index particles having a hollow structure or a porous structure is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10% or more and 40% or less from the viewpoints of increasing the refractive index of the obtained optical functional layer, finely adjusting the refractive index, and durability.

[0068] The method for measuring the porosity of high refractive index particles is not particularly limited and can be appropriately selected depending on the purpose. For example, the porosity can be measured using a Poremaster (Anton Paar), a gas adsorption specific surface area / pore size distribution analyzer (manufactured by Seika Digital Image Co., Ltd.) using a gas adsorption method, or by examining the relationship between the apparent density D1 and true density D0 of the particles.

[0069] The shape of the high refractive index particles is not particularly limited and can be appropriately selected depending on the purpose, and may be, for example, regular or irregular. Examples of regular high refractive index particles include spherical, plate-like, flaky, rod-like, columnar, needle-like, dendritic, spongy, angular, and elliptical shapes.

[0070] The size of the high refractive index particles is not particularly limited and can be appropriately selected depending on the purpose, but the average primary particle diameter is preferably 1 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less. For example, from the viewpoint of excellent haze reduction effect, the average primary particle diameter of the high refractive index particles is preferably 100 nm or less. Note that the particle size may be appropriately adjusted depending on the application.

[0071] The method for measuring the particle size of high refractive index particles is not particularly limited and can be appropriately selected depending on the purpose. For example, the particle size can be measured using a particle size distribution analyzer using dynamic light scattering (VASCO, manufactured by CORDUAN), a laser diffraction particle size distribution analyzer (Partica LA-960V2, manufactured by HORIBA, Ltd.), or cross-sectional observation using a heated cathode field-scanning electron microscope (Schottky FE-SEM).

[0072] The particles may be appropriately synthesized or commercially available. There are no particular limitations on commercially available low refractive index particles and they can be selected appropriately depending on the purpose, and examples of such products include Techpolymer (manufactured by Sekisui Plastics Co., Ltd.) and TMPS (manufactured by Taiyo Kagaku Co., Ltd.). There are no particular limitations on commercially available high refractive index particles and they can be selected appropriately depending on the purpose, and examples of such products include Zircostar (manufactured by Nippon Shokubai Co., Ltd.) and titanium oxide nanoparticle dispersion (manufactured by Daihachi Chemical Industry Co., Ltd.).

[0073] Here, an embodiment of the optical member of the present invention will be described with reference to the drawings, although the present invention is not limited to these embodiments.

[0074] In each drawing, the same components are denoted by the same reference numerals, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0075] In one embodiment of the optical member of the present invention, the refractive index of the optical functional layer decreases from the layer region in contact with the substrate toward the outermost layer of the optical functional layer. Details will be described with reference to FIG. 1A.

[0076] [Figure 1A] 1A is a schematic cross-sectional view showing an optical member according to one embodiment of the present invention. The optical member 101 has a base 1 and an optical functional layer 20 on the base 1. The optical functional layer 20 includes particles 31 and a resin 32. The optical functional layer 20 has a plurality of layer regions 21-27, which are divided into 100-segment sections in the thickness direction of the optical functional layer 20 from the interface between the base 1 and the optical functional layer 20. More specifically, the optical functional layer 20 has a first layer region 21 on the base 1, a second layer region 22 on the first layer region 21, a third layer region 23 on the second layer region 22, a fourth layer region 24 on the third layer region 23, a fifth layer region 25 on the fourth layer region 24, a sixth layer region 26 on the fifth layer region 25, and a seventh layer region 27 on the sixth layer region 26.

[0077] For convenience, FIG. 1A shows the optical functional layer 20 as seven layer regions, but the number of layer regions in the optical functional layer 20 is not particularly limited and can be set appropriately depending on the application of the optical component and the degree of modulation of the refractive index.

[0078] For example, when it is desired to modulate the refractive index between layer regions in the optical functional layer by 0.01 increments to modulate the refractive index of the optical functional layer from 1.2 to 1.5, the number of layer regions in the optical functional layer is preferably 30 to 60. In this case, if the number of layer regions in the optical functional layer is 60 or less, problems such as reduced adhesion between the optical functional layers and reduced productivity due to a longer curing time can be resolved.

[0079] For example, when it is desired to modulate the refractive index between layer regions in the optical functional layer by 0.1 increments to modulate the refractive index of the optical functional layer from 1.2 to 1.5, the number of layer regions in the optical functional layer is preferably 3 to 7. In this case, if the number of layer regions in the optical functional layer is 7 or less, it is possible to eliminate the problem that particles are unevenly distributed within the optical functional layer, making it impossible to form a desired refractive index gradient.

[0080] In the optical member of the present invention, the refractive index difference between at least one pair of adjacent layer regions in the optical functional layer is greater than 0 and not greater than 0.1. In Fig. 1A, the refractive index difference between a first layer region 21 and a second layer region 22 adjacent to the first layer region 21 is greater than 0 and not greater than 0.1. Similarly, the refractive index difference between the second layer region 22 and a third layer region 23 adjacent to the second layer region 22 is greater than 0 and not greater than 0.1. Similarly, the refractive index difference between the third layer region 23 and the fourth layer region 24, the fourth layer region 24 and the fifth layer region 25, the fifth layer region 25 and the sixth layer region 26, and the sixth layer region 26 and the seventh layer region 27 are all greater than 0 and not greater than 0.1.

[0081] 1A, the liquid composition forming the first layer region 21 is prepared so that the content ratio of particles 31 in the liquid composition is lower than that of the other layer regions 22 to 27. As a result, the refractive index of the first layer region 21 obtained by curing is higher than that of the other layer regions 22 to 27. The content ratio of particles 31 in the liquid composition is adjusted so that the difference between the refractive index of the second layer region 22 obtained by curing and that of the first layer region 21 is greater than 0 and not more than 0.1, and the refractive index of the second layer region 22 is lower than that of the first layer region 21. The same applies to the subsequent layer regions 22 to 27. As a result, an optical element 101 is obtained in which the refractive index decreases from the interface between the base 1 and the optical functional layer 20, i.e., from the interface between the base 1 and the first layer region 21, toward the seventh layer region 27, the outermost layer of the optical functional layer 20.

[0082] By adopting such a configuration, it is possible to maintain the reflectance at a constant value regardless of the wavelength region or the angle of incident light, that is, it is possible to suppress the wavelength dependency of the optical member.

[0083] Another embodiment of the optical member of the present invention is one in which the refractive index increases from the layer region of the optical functional layer that is in contact with the substrate toward the layer region of the outermost layer of the optical functional layer. Details will be described with reference to FIG. 1B.

[0084] [Figure 1B] 1B is a schematic cross-sectional view showing an optical member according to another embodiment of the present invention. The optical member 102 has a base 1 and an optical functional layer 20 on the base 1. The optical member 102 has the same configuration as the optical member 101 in FIG. 1A, except that the refractive index of the optical functional layer increases from the layer region in contact with the base toward the outermost layer region of the optical functional layer, and therefore redundant description will be omitted.

[0085] When the optical member of the present invention contains particles, the particles are preferably distributed at the interface between adjacent layer regions in the optical functional layer, as will be described in detail below with reference to FIG.

[0086] [Figures 2A and 2B] Fig. 2A is a schematic cross-sectional view showing an optical member according to another embodiment of the present invention, and Fig. 2B is a schematic enlarged view of an interface between adjacent layer regions in the optical functional layer of Fig. 2A.

[0087] The mechanism by which the refractive index of adjacent layer regions 21 to 27 in the optical functional layer 20 changes is as follows. For example, when a liquid composition is applied onto layer region 21 to form layer region 22, resin 32 present on the surface of layer region 21, which becomes the underlying layer, dissolves. When the liquid composition applied onto layer region 21 is cured in this state, particles 31 are distributed at the interface between adjacent layer regions 21 and 22. When the optical member has such a structure, the refractive index distribution occurring along the thickness direction of the substrate 1 can be modulated more gradually, and the refractive index can be controlled with higher precision.

[0088] In each of the layer regions 21 to 27 of the optical function layer, it is preferable that the particles 31 are uniformly distributed in the thickness direction of the optical function layer in the single layer region. When the particles 31 are uniformly distributed in the thickness direction of the optical function layer in the single layer region, the particles 31 absorb and disperse stress applied to the optical function layer, thereby improving the strength of the entire optical function layer.

[0089] Another embodiment of the optical member of the present invention has regions with different refractive indices in the plane direction of the optical functional layer, as shown in FIG. 4A described later.

[0090] In this specification, "a state in which particles are uniformly distributed" means that the particle abundance ratio in any section is constant throughout the thickness direction of the optical functional layer in the single layer region and throughout the direction intersecting the thickness direction of the optical functional layer in the single layer region, or that there is little variation in the ratio.

[0091] The phrase "a state in which particles are not uniformly distributed" refers to a case in which particles are unevenly distributed at specific locations in the thickness direction of the optical functional layer in the single layer region and in a direction intersecting the thickness direction of the optical functional layer in the single layer region, for example, at least one of the upper, center, and lower portions in the thickness direction of the optical functional layer in the single layer region.

[0092] The method for confirming the state of particles in the optical functional layer is not particularly limited and can be selected appropriately depending on the purpose. For example, the state can be confirmed by observing the two-dimensional cross section using a heated cathode field-type scanning electron microscope (Schottky FE-SEM), or by processing and exposing the sample using a focused ion beam device and then observing the three-dimensional cross section using a scanning electron microscope (FIB / SEM cross beam device NVision40, manufactured by Carl ZEISS (SII-NT)), obtaining image data at several locations in the thickness direction of the substrate and in a direction intersecting the thickness direction of the substrate, and calculating the particle ratio by image processing.

[0093] The optical functional layer of the optical member of the present invention preferably contains at least two types of particles having different refractive indices.

[0094] In the optical member of the present invention, it is preferred that the low refractive index particles are exposed on the outermost surface of the optical functional layer, since when the optical member has such a structure, the refractive index of the surface of the optical member can be further reduced.

[0095] The method for exposing low refractive index particles on the outermost surface of the optical functional layer is not particularly limited and can be appropriately selected depending on the purpose. Examples include a method of applying low refractive index particles (or a liquid composition containing low refractive index particles) to the outermost surface of the optical functional layer, and a method of abrading a part of the optical functional layer that already contains low refractive index particles to expose the low refractive index particles.

[0096] The method for confirming the structure of the optical member of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, the structure can be confirmed by the following method.

[0097] The presence of a substrate and an optical functional layer in the optical element of the present invention can be confirmed by evaluating the reflectance of the optical element in the visible range (380 nm to 780 nm) using a spectrophotometer (V-770, manufactured by JASCO Corporation) with an incident angle set to 5°.

[0098] There are no particular limitations on the method for confirming particle distribution at the interface between each layer region in the optical functional layer, and it can be selected appropriately depending on the purpose. For example, it can be confirmed by adding fluorescent particles as particles, stacking them, and mapping the fluorescent particles using time-of-flight secondary ion mass spectrometry (TOF.SIMS5, manufactured by ION-TOF). It can also be confirmed by observing 2D cross sections using a heated cathode field-effect scanning electron microscope (Schottky FE-SEM), or by processing and exposing the sample using a focused ion beam device and observing 3D cross sections using a scanning electron microscope (FIB / SEM crossbeam system NVision40, manufactured by Carl ZEISS (SII-NT)) to observe whether particles are distributed along the dividing lines that separate each region in the thickness direction.

[0099] [Average reflectance of optical components] The reflectance of the optical member is not particularly limited and can be appropriately selected depending on the purpose, but when the reflectance of the optical member is controlled to be low, the average reflectance in the visible range (380 nm to 780 nm) is set to less than 5.0%. When the reflectance of the optical member is controlled to be low, the average reflectance in the visible range (380 nm to 780 nm) is preferably 0.5% or more and less than 5.0%.

[0100] When the reflectance of the optical member is controlled to be high, the average reflectance in the visible range (380 nm to 780 nm) is preferably 7.0% or more.

[0101] The reflectance of the optical member is measured using a spectrophotometer (for example, V-770, manufactured by JASCO Corporation) with the incident angle set to 5° under the conditions described in the examples.

[0102] [Wavelength dependence of optical components] The wavelength dependence of the optical element is not particularly limited and can be selected appropriately depending on the purpose, but it is preferable that the difference between the maximum reflectance in the visible range measured at an incident angle of 5° of the optical element and the minimum reflectance in the visible range measured at an incident angle of 5° of the optical element is 5% or less.

[0103] When the reflectance of an optical member is controlled to be low, the absolute value of the wavelength dependency of the optical member is preferably 0.5% to 3.0%, more preferably less than 0.5%, and when the reflectance of an optical member is controlled to be high, the absolute value of the wavelength dependency of the optical member is preferably 0.5% to 5.0%, more preferably less than 0.5%.

[0104] The wavelength dependency of the optical member is measured using a spectrophotometer (for example, V-770, manufactured by JASCO Corporation) with the incident angle set to 5° under the conditions described in the examples.

[0105] [Average transmittance of optical components] The average transmittance of the optical member is not particularly limited and can be appropriately selected depending on the purpose, but when the optical member is controlled to have a low reflectance, the average transmittance when the incident angle is set to 0° is preferably 70% or more, more preferably 95% or more. When the optical member is controlled to have a high reflectance, the average transmittance when the incident angle is set to 0° is preferably 70% or more, more preferably 85% or more.

[0106] The transmittance of the optical member is measured using a spectrophotometer (for example, V-770, manufactured by JASCO Corporation) with the angle of incidence set to 0° under the conditions described in the examples.

[0107] [Haze value of optical components] The haze value of the optical member is not particularly limited and can be appropriately selected depending on the purpose, but when the optical member is controlled to have a low reflectance, it is preferably less than 30%, more preferably less than 1.0%, and when the optical member is controlled to have a high reflectance, it is preferably less than 30%, more preferably less than 10%.

[0108] The haze value of the optical member is measured using a haze meter (for example, NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS-K-7136:2000 (ISO 14782:1999).

[0109] The optical member of the present invention has the above-described configuration, and can be an optical member that can arbitrarily control the reflectance, has excellent film strength, and has small wavelength dependency of the reflectance. The optical member of the present invention preferably further has excellent adhesion between the layer regions of the optical functional layer.

[0110] (Method of manufacturing optical members) The method for producing an optical member of the present invention includes a film forming step, a film curing step, and an optically functional layer forming step, and may include other steps as necessary.

[0111] The optical member manufacturing apparatus according to the present invention includes a film forming means, a film curing means, and an optical functional layer forming means, and may include other means as necessary. The optical member manufacturing method according to the present invention can be suitably carried out by the optical member manufacturing apparatus.

[0112] The method for producing an optical member of the present invention and the apparatus for producing an optical member of the present invention can suitably produce the optical member of the present invention.

[0113] <Film formation process> The film-forming step is a step of forming a film by discharging a liquid composition containing particles onto a substrate. The film-forming means is a means of forming a film by discharging a liquid composition containing particles. The film-forming step can be suitably carried out by the film-forming means.

[0114] In the optical functional layer forming step described later, a film forming step and a film curing step described later are repeated to form an optical functional layer having a uniform thickness. The optical functional layer forming step includes two or more film forming steps in which the content ratio of the particles contained in the liquid composition is different so that when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the difference in refractive index between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1.

[0115] The thickness of one layer formed in the film formation step is preferably 1 nm to 200 nm, more preferably 10 nm to 100 nm. By setting the thickness of one layer formed in the film formation step to 1 nm to 200 nm, the refractive index difference between each layer region of the optical functional layer can be set within a suitable range.

[0116] The film formation method is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include wet processes such as a dispenser method, a spin coating method, an inkjet method, etc. Among these, the inkjet method is preferred from the viewpoints of high material usage efficiency, no need for a plate, and cost reduction.

[0117] Examples of inkjet methods include a charge control method that uses electrostatic attraction to eject a liquid composition, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electric signal into an acoustic beam and irradiates the liquid composition, thereby ejecting it using radiation pressure, and a thermal inkjet (Bubble Jet (registered trademark)) method that heats the liquid composition to form bubbles and uses the resulting pressure.

[0118] The droplets of the liquid composition are controlled primarily by the print head. In the case of a thermal inkjet system, the droplet volume can be controlled by the structure of the print head. That is, droplets of a desired size can be ejected by changing the sizes of the ink chamber, heating unit, and nozzle. Furthermore, even in the case of a thermal inkjet system, it is possible to eject droplets of a variety of sizes by providing multiple print heads with different sizes of heating unit and nozzle.

[0119] In the case of the drop-on-demand method using piezoelectric elements, it is possible to change the droplet volume due to the structure of the print head, just as with the thermal inkjet method, but it is also possible to eject droplets of multiple sizes using a print head with the same structure by controlling the waveform of the drive signal that drives the piezoelectric element.

[0120] When the liquid composition is ejected by an inkjet method, the amount of the liquid to be ejected is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of resolution and productivity, it is preferably 1 pL or more and 100 pL or less.

[0121] When ejecting a liquid composition using an inkjet method, by using at least two liquid compositions with different refractive indices, the optical functional layer cured in the optical functional layer-forming step has a cured product with at least two different refractive indices. Two liquid compositions with different refractive indices may also be used in the film-forming step. Herein, when two liquid compositions with different refractive indices are used, a liquid composition capable of forming a cured product with a relatively lower refractive index than the cured product of one of the liquid compositions is referred to as a "low refractive index liquid composition." When two liquid compositions with different refractive indices are used, a liquid composition capable of forming a cured product with a relatively higher refractive index than the cured product of one of the liquid compositions is referred to as a "high refractive index liquid composition." When three or more liquid compositions with different refractive indices are used in the film-forming step, a liquid composition capable of forming a cured product with the highest refractive index is referred to as a "high refractive index liquid composition," and a liquid composition capable of forming a cured product with the lowest refractive index is referred to as a "low refractive index liquid composition."

[0122] In this specification, when there is no need to distinguish between the "high refractive index liquid composition" and the "low refractive index liquid composition", they may be simply referred to as the "liquid composition".

[0123] When the liquid composition is ejected by an inkjet method, the ejection amounts of at least two liquid compositions having different refractive indices may be changed in the film formation step, thereby enabling the production of optical elements having a wider variety of structures.

[0124] The amount of each liquid composition ejected in one go is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoints of resolution and productivity, it is preferably from 0.1 pL to 100 pL, and more preferably from 1 pL to 30 pL. Here, when the liquid composition is ejected by inkjet, the amount ejected in one go refers to the total amount ejected from multiple holes in the inkjet head in one ejection.

[0125] For example, the amount of high refractive index liquid composition ejected at one time may be set to be large (e.g., 5 pL) and the amount of low refractive index liquid composition ejected at one time may be set to be small (e.g., 2 pL), or the amount of high refractive index liquid composition ejected at one time may be set to be small (e.g., 2 pL) and the amount of low refractive index liquid composition ejected at one time may be set to be large (e.g., 5 pL).

[0126] When the liquid composition is ejected by an inkjet method, the resolution is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of changing the refractive index in a direction intersecting the thickness direction of the substrate, it is preferably 20 dpi or more.

[0127] The film formation step preferably includes ejecting at least two liquid compositions having different refractive indices onto a substrate by an inkjet method to form a print pattern in a direction intersecting the thickness direction of the substrate. Forming the print pattern involves ejecting the liquid compositions so that one liquid composition is adjacent to another liquid composition having a refractive index different from that of the first liquid composition in the direction intersecting the thickness direction of the substrate.

[0128] When it is said that one liquid composition is adjacent to another liquid composition having a different refractive index from that of the first liquid composition, it is preferable that droplets of the first liquid composition are adjacent to droplets of the other liquid composition having a different refractive index from that of the first liquid composition.

[0129] More specifically, the printing pattern is formed by discharging droplets of one liquid composition onto a substrate, and then discharging droplets of another liquid composition having a refractive index different from that of the first liquid composition so that the droplets come into contact with a portion of the first liquid composition, and discharging the droplets of the other liquid composition so that the center of the droplet of the other liquid composition is outside the outer edge of the droplet of the first liquid composition, thereby arranging droplets of at least two liquid compositions with different refractive indices adjacent to each other.

[0130] As used herein, "droplets of one liquid composition are adjacent to droplets of another liquid composition having a different refractive index from the first liquid composition in a direction intersecting the thickness direction of the substrate" means that a portion of the ejected droplets of one liquid composition comes into contact with a portion of the droplets of the other liquid composition. When a portion of the ejected droplets of one liquid composition comes into contact with a portion of the droplets of the other liquid composition, the liquid compositions may be partially mixed to the extent that the refractive index of each liquid composition remains unchanged. When this step is included, the optical functional layer shown in FIG. 4A can also be formed.

[0131] 3A and 3B are schematic top views showing an example of the state of droplets of a liquid composition for one scan when they land in a film formation step of a method for manufacturing an optical component according to one embodiment of the present invention, respectively.

[0132] Figure 3A shows a state in which the outer edge of a droplet of one liquid composition 42 is in contact with the outer edge of a droplet of another liquid composition 41 adjacent to the droplet of one liquid composition 42, and the center X2 of the droplet of the other liquid composition 41 is outside the outer edge of the droplet of one liquid composition 42.

[0133] Figure 3B shows that the outer edge of a droplet of one liquid composition 42 intersects with the outer edge of a droplet of another liquid composition 41 adjacent to the droplet of one liquid composition 42, and the center X2 of the droplet of the other liquid composition 41 is outside the outer edge of the droplet of one liquid composition 42.

[0134] In this specification, the center of a droplet of a liquid composition can be identified by the following method. After the film formation process, a top-view image of the droplet of the liquid composition is taken, and the outer edge of the droplet of the liquid composition is identified by image analysis. Next, if the identified outer edge is an ellipse, the major axis and the minor axis of the ellipse are identified. The intersection of these major and minor axes is defined as the center of the droplet of the liquid composition. Furthermore, if the identified outer edge is a perfect circle, the point where the perpendicular bisectors of three arbitrarily selected points on the outer edge intersect is defined as the center of the droplet of the liquid composition. Furthermore, if the identified outer edge is irregular, the center of gravity of the droplet is considered to be the center of the droplet. The center of gravity of a droplet with an irregular outer edge is the intersection of two vertical lines drawn when the droplet is rotated around an arbitrary axis of rotation.

[0135] 3B , in a state in which the outer edge of a droplet of first liquid composition 42 intersects with the outer edge of a droplet of another liquid composition 41 adjacent to the droplet of first liquid composition 42 and the center X2 of the droplet of the other liquid composition 41 is outside the outer edge of the droplet of first liquid composition 42, when the total area of ​​either the droplet of first liquid composition 42 or the droplet of the other liquid composition 41 in a top view is taken as 100%, the area of ​​the overlapping portion between the droplet of first liquid composition 42 and the droplet of the other liquid composition 41 is not particularly limited, but is preferably less than 50%. Note that when the size of the droplet of first liquid composition 42 and the size of the droplet of the other liquid composition 41 are different, the droplet with the smaller size is taken as the droplet with the total area of ​​100%.

[0136] Next, a specific example of an optical component according to an embodiment in which a print pattern is formed in the film forming step will be described.

[0137] [Figures 4A and 4B] Fig. 4A is a schematic cross-sectional view showing a state after an optical functional layer forming step in a method for producing an optical member according to one embodiment of the present invention, and Fig. 4B is a schematic top view showing printing patterns for forming each layer in Fig. 4A.

[0138] 4A, the optical member 103 has a base 1 and an optical functional layer 20 provided on the base 1. The optical functional layer 20 has a plurality of layer regions 21 to 23 that are divided at intervals of 100 nm from the interface between the base 1 and the optical functional layer 20 in the thickness direction of the optical functional layer 20. The optical member 103 has the same configuration as the optical member 101 in FIG. 1A except that the refractive index changes in the direction intersecting the thickness direction of the optical functional layer 20, and therefore a redundant description will be omitted.

[0139] As shown in Figure 4B, the first layer region 21 and the third layer region 23 are provided with the respective liquid compositions on the substrate 1 so that the refractive index changes in at least one direction intersecting the thickness direction of the substrate 1.

[0140] Specifically, the first layer region 21 is provided with a higher proportion of high-refractive-index liquid composition 42 at the left end of the first layer region 21 in Fig. 4B. Furthermore, the proportion of low-refractive-index liquid composition 41 is provided so as to gradually increase from the left end toward the right end of the printing pattern for forming the first layer region 21 in Fig. 4B. Furthermore, the proportion of low-refractive-index liquid composition 41 is provided so as to increase at the right end of the printing pattern for forming the first layer region 21 in Fig. 4B. As a result, the refractive index of the first layer region 21 is relatively lower at the right end than at the left end, and the refractive index of the first layer region 21 gradually decreases from the right end toward the left end.

[0141] In the printing pattern for forming the third layer region 23 in Fig. 4B, the proportion of the low refractive index liquid composition 41 is applied so that it is greater on the left side. Furthermore, the proportion of the high refractive index liquid composition 42 is applied so that it gradually increases from the left side to the right side of the printing pattern for forming the third layer region 23 in Fig. 4B. Furthermore, the proportion of the high refractive index liquid composition 42 is applied so that it is greater on the right side of the third layer region 23 in Fig. 4B. Accordingly, the refractive index of the third layer region 23 is relatively lower on the left side than on the right side, and the refractive index of the third layer region 23 gradually increases from the left side to the right side.

[0142] 4B, droplets of the low-refractive-index liquid composition 41 and droplets of the high-refractive-index liquid composition 42 are applied so as to be in contact with each other in a staggered manner (in a checkerboard pattern). As a result, the refractive index of the entire second layer region 22 is approximately uniform and medium. Here, "medium" means that the refractive index is approximately the same as the refractive index of the central portion between the right and left end sides of the first layer region 21, or the refractive index of the central portion between the right and left end sides of the third layer region 23.

[0143] The checkered second layer region 22 is obtained by alternately ejecting droplets of the low refractive index liquid composition 41 and the high refractive index liquid composition 42. In the second layer region 22, similar to the first layer region 21 and the third layer region 23, each liquid composition may be applied so that the refractive index varies. An optical element having such a structure can be suitably employed, for example, as an optical filter that reflects a specific wavelength.

[0144] Alternatively, a film may be formed by randomly discharging droplets of the refractive index liquid composition 41 and the high refractive index liquid composition 42 onto the substrate 1.

[0145] An optical member having such a structure has the effect of reflecting specific wavelengths due to the change in refractive index within the plane, and can therefore be suitably employed as, for example, an optical filter.

[0146] By using at least two liquid compositions with different refractive indices, an optical element can be formed in which the refractive index changes in the thickness direction of the optical functional layer and in at least one direction intersecting the thickness direction of the optical functional layer, as shown in Figure 4A. The refractive index difference between one layer region and other layer regions in such an optical element can be determined from the refractive index of each layer region in the overlapping region of the layer regions of the optical functional layer in the stacking direction.

[0147] There are no particular limitations on "at least one direction intersecting the thickness direction of the substrate" or "at least one direction in the plane of the optical functional layer" and these can be selected appropriately depending on the purpose, such as a direction from one end of the optical functional layer to the opposing other end, or a direction from any position on the optical functional layer to another any position. Therefore, the start point and end point in "at least one direction intersecting the thickness direction of the substrate" or "at least one direction in the plane of the optical functional layer" can be selected appropriately depending on the purpose.

[0148] Examples of a method for ejecting at least two liquid compositions with different refractive indices in at least one direction intersecting the thickness direction of the substrate so that the refractive index changes include a method for alternately ejecting one liquid composition and another liquid composition with a refractive index different from that of the first liquid composition, and a method for alternately ejecting droplets of one liquid composition and another liquid composition with a refractive index different from that of the first liquid composition is preferred.

[0149] From the viewpoint of improving adhesion and wettability with the substrate in the film formation step, a primer ink may be applied onto the substrate and / or optical functional layer as a pre-treatment and / or post-treatment.

[0150] The primer ink may contain, for example, a polymerizable compound, a polymerization initiator, an organic solvent, a surfactant, and the like.

[0151] The polymerizable compound is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the polymerizable compound contains at least one adhesion-promoting component selected from the group consisting of N-vinyl lactam compounds, acrylamide compounds, and N-vinyl amide compounds.

[0152] The polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include those that can generate active species such as radicals or cations by the energy of active energy rays and initiate polymerization of polymerizable compounds (monomers or oligomers). As such polymerization initiators, known radical polymerization initiators, cationic polymerization initiators, base generators, etc. can be used alone or in combination of two or more, and among these, it is preferable to use a radical polymerization initiator.

[0153] The thickness of the applied primer ink is not particularly limited and can be set appropriately taking into consideration the liquid composition, the required adhesive performance, and optical performance, etc., but is preferably 0.1 μm to 5 μm, more preferably 0.5 μm to 3 μm, and even more preferably 1 μm to 2 μm. When the applied thickness of the primer ink is 0.1 μm or more, the ink is provided with fixability and permeability. When the applied thickness of the primer ink is 5 μm or less, the drying speed after application of the primer ink can be shortened.

[0154] The physical properties of the primer ink are not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferable that the viscosity and surface tension are within the following ranges.

[0155] The viscosity of the primer ink at 25°C is preferably from 5 mPa·s to 20 mPa·s, and more preferably from 5 mPa·s to 15 mPa·s, in order to obtain good ejection properties. The viscosity can be measured, for example, using a rotational viscometer (viscometer TVE-25L, manufactured by Tokyo Glass Instruments Co., Ltd.) or a rheometer (MCR302, manufactured by Anton Paar).

[0156] The surface tension of the primer ink is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 10 mN / m or more, more preferably 20 mN / m or more, and preferably 40 mN / m or less, and more preferably 30 mN / m or less. If the surface tension of the primer ink is 10 mN / m or more, the problem of ejected droplets breaking up can be eliminated. If the surface tension of the primer ink is 40 mN / m or less, the problem of droplets becoming difficult to level, which impairs the uniformity of the coating film, can be eliminated.

[0157] The method for measuring the surface tension of the primer ink is not particularly limited and can be appropriately selected depending on the purpose. For example, the surface tension can be measured using a surface tensiometer (DY-300, manufactured by Kyowa Interface Science Co., Ltd.).

[0158] The primer ink may be an appropriately synthesized one or a commercially available product, such as PR100 (manufactured by Mimaki Engineering Co., Ltd.).

[0159] <<Liquid composition>> Next, the liquid composition used in the film formation step will be described. The liquid composition contains particles, and may contain a solvent and other components as necessary. The refractive index of the optical functional layer in the present invention can be adjusted by at least one of the type and content of particles contained in the liquid composition. As the particles, those described in the <<Particles>> section of (Optical Members) can be used.

[0160] The liquid composition of the present invention may contain a suitable mixture of high-refractive-index particles and low-refractive-index particles so that the resulting optical functional layer has a desired refractive index.

[0161] When a liquid composition containing a mixture of high-refractive-index particles and low-refractive-index particles is used, increasing the content of the high-refractive-index particles in the liquid composition increases the refractive index of the liquid composition, while increasing the content of the low-refractive-index particles in the liquid composition decreases the refractive index of the liquid composition.

[0162] The method for measuring the refractive index of the liquid composition is not particularly limited and can be appropriately selected depending on the purpose. For example, each liquid composition is applied to an arbitrary substrate by spin coating to a film thickness of 100 nm, and the refractive index of the film thus produced is measured using a spectroscopic ellipsometer M-2000 (manufactured by JA Woollam Japan).

[0163] The liquid composition is not particularly limited and can be appropriately selected depending on the purpose. For example, it may be a curable liquid composition or a plastic liquid composition, but is preferably a curable liquid composition.

[0164] The liquid composition may be so formulated that it foams during the film curing step, causing voids in the resulting film.

[0165] <<<Solvent>>> The solvent is not particularly limited and can be appropriately selected depending on the purpose, and preferred are, for example, those capable of dissolving or dispersing each component, those that are easily homogenized in the film-forming step and the film-hardening step, those that have excellent liquid storage properties, and those that have an appropriate saturated vapor pressure. Specifically, from the viewpoint of the drying load, in order to adjust the drying rate, solvents having a boiling point of 50°C or more and 300°C or less at normal pressure and normal temperature are preferred, and solvents having a boiling point of 100°C or more and 200°C or less are more preferred.

[0166] Examples of solvents having a boiling point of less than 100°C include hydrocarbons such as hexane (boiling point: 68.7°C), heptane (boiling point: 98.4°C), cyclohexane (boiling point: 80.7°C), and benzene (boiling point: 80.1°C); halogenated hydrocarbons such as dichloromethane (boiling point: 39.8°C), chloroform (boiling point: 61.2°C), carbon tetrachloride (boiling point: 76.8°C), 1,2-dichloroethane (boiling point: 83.5°C), and trichloroethylene (boiling point: 87.2°C); diethyl ether (boiling point: 34.6°C), diisopropyl ether (boiling point: 68.5°C), dipropyl ether (boiling point: 90.5°C), and tetrahydrofuran (boiling point: ethers such as ethyl formate (boiling point: 54.2°C), methyl acetate (boiling point: 57.8°C), ethyl acetate (boiling point: 77.1°C), isopropyl acetate (boiling point: 89°C), ketones such as acetone (boiling point: 56.1°C), 2-butanone (boiling point: 79.6°C), alcohols such as methanol (boiling point: 64.5°C), ethanol (boiling point: 78.3°C), 2-propanol (boiling point: 82.4°C), 1-propanol (boiling point: 97.2°C), cyano compounds such as acetonitrile (boiling point: 81.6°C), propionitrile (boiling point: 97.4°C), and carbon disulfide (boiling point: 46.2°C).

[0167] Among these, cellosolves, ketones, esters, ethers, and alcohols are preferred.

[0168] Examples of solvents with a boiling point of 100°C or higher include propylene glycol monomethyl ether (boiling point: 120.0°C), octane (boiling point: 125.7°C), toluene (boiling point: 110.6°C), xylene (boiling point: 138°C), tetrachloroethylene (boiling point: 121.2°C), chlorobenzene (boiling point: 131.7°C), dioxane (boiling point: 101.3°C), dibutyl ether (boiling point: 101.3°C), and propylene glycol monomethyl ether (boiling point: 101.3°C). 1-Butanol (boiling point: 117.7°C), N,N-dimethylformamide (boiling point: 153°C), N,N-dimethylacetamide (boiling point: 166°C), and dimethyl sulfoxide (boiling point: 189°C).

[0169] Among these, cellosolves, ketones, esters, ethers, and alcohols are preferred.

[0170] The content of the solvent is not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferably added so that the solid content concentration is 2% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less. By adding the solvent so that the solid content concentration is 2% by mass or more, it is possible to suppress the occurrence of problems such as film thickness unevenness due to the long drying time. By adding the solvent so that the solid content concentration is 30% by mass or less, uneven particle distribution does not occur, the coating amount is reduced, and problems such as coating unevenness can be suppressed.

[0171] The solvent may be suitably synthesized or may be a commercially available product. The commercially available solvent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include trade names such as propylene glycol monomethyl ether (manufactured by Kanto Chemical Co., Ltd.), methyl ethyl ketone (manufactured by Kanto Chemical Co., Ltd.), and propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.).

[0172] <<<Other ingredients>>> Other components contained in the liquid composition are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include resins, crosslinking agents, photopolymerization initiators (also simply referred to as "initiators" or "photoinitiators"), photosensitizers, surfactants, rheology control agents, antioxidants, and antifungal agents.

[0173] -resin- The resin is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that it has good compatibility with each component and can disperse particles. Specific examples include non-curable resins that do not require curing treatment and curable resins that require curing treatment.

[0174] --Non-curing resin-- Non-curable resins are classified into low refractive index resins and high refractive index resins based on their refractive index.

[0175] ---Low refractive index resin--- The refractive index of the low refractive index resin is not particularly limited and can be appropriately selected depending on the purpose, but is less than 1.5. The low refractive index resin is not particularly limited and can be appropriately selected depending on the purpose as long as the refractive index is less than 1.5, and examples thereof include (meth)acrylic resins (e.g., polymethyl methacrylate), siloxane resins, and norbornene resins (e.g., polynorbornene). These may be used alone or in combination of two or more.

[0176] The low refractive index resin may contain a fluorine-containing resin from the viewpoint of reducing the refractive index. The fluorine-containing resin is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include tetrafluoroethylene-perfluorodioxole copolymer (refractive index: 1.35), tetrafluoroethylene-hexafluoropropylene copolymer (refractive index: 1.34), polytrifluoroethyl methacrylate (refractive index: 1.42), polytetrafluoroethylene (refractive index: 1.35 to 1.38), and hexafluoroisopropyl (meth)acrylate (refractive index: 1.31 to 1.33).

[0177] ---High refractive index resin--- The refractive index of the high refractive index resin is not particularly limited and can be selected appropriately depending on the purpose, but is 1.5 or more. The high refractive index resin is not particularly limited and can be selected appropriately depending on the purpose as long as the refractive index is 1.5 or more, and examples thereof include resins containing aromatic rings, resins containing halogen elements other than fluorine, and resins containing atoms such as S (sulfur), N (nitrogen), or P (phosphorus). These may be used alone or in combination of two or more.

[0178] The resin containing an aromatic ring is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include styrene resins such as polystyrene, polycarbonates such as polyethylene terephthalate, polyvinylcarbazole, and bisphenol A, and compounds containing a fluorene skeleton.

[0179] The resin containing a halogen element other than fluorine is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include polyvinyl chloride, polytetrabromobisphenol A glycidyl ether, etc. Here, examples of the "halogen element other than fluorine" include Br (bromine), I (iodine), Cl (chlorine), etc.

[0180] Examples of resins containing atoms such as S (sulfur), N (nitrogen), or P (phosphorus) include polybisphenol S glycidyl ether and polyvinylpyridine.

[0181] --Curable resin-- As the curable resin, a resin component containing a monomer or oligomer having a reactive group that crosslinks by heat or ionizing radiation is preferred, a resin component containing a polyfunctional monomer or polyfunctional oligomer having two or more functional groups is more preferred, and a resin component containing a polyfunctional monomer or polyfunctional oligomer having three or more functional groups is even more preferred.

[0182] These may be used alone or in combination of two or more.

[0183] The functional group of the polyfunctional monomer or polyfunctional oligomer that is cured by ionizing radiation is preferably a photopolymerizable functional group, an electron beam polymerizable functional group, or a radiation polymerizable functional group, and more preferably a photopolymerizable functional group.

[0184] The photopolymerizable functional group is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include (meth)acryloyl groups, alkenyl groups, cinnamoyl groups, cinnamylideneacetyl groups, benzalacetophenone groups, styrylpyridine groups, α-phenylmaleimide groups, phenyl azide groups, sulfonyl azide groups, carbonyl azide groups, diazo groups, o-quinonediazide groups, furyl acryloyl groups, coumarin groups, pyrone groups, anthracene groups, benzophenone groups, stilbene groups, dithiocarbamate groups, xanthate groups, 1,2,3-thiadiazole groups, cyclopropene groups, and azadioxabicyclo groups. These may be used alone or in combination of two or more.

[0185] The photopolymerizable polyfunctional monomer is not particularly limited and can be appropriately selected depending on the purpose. For example, (meth)acrylic acid diesters of alkylene glycols such as neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, and propylene glycol di(meth)acrylate; polyoxyalkylenes such as triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol triacrylate, and polypropylene glycol di(meth)acrylate; Examples include (meth)acrylic acid diesters of glycols; (meth)acrylic acid diesters of polyhydric alcohols such as pentaerythritol di(meth)acrylate and pentaerythritol tri(meth)acrylate; (meth)acrylic acid diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis{4-(acryloxy-diethoxy)phenyl}propane and 2,2-bis{4-(acryloxy-polypropoxy)phenyl}propane; epoxy (meth)acrylates, urethane (meth)acrylates, and polyester (meth)acrylates.

[0186] Curable resins are classified based on their refractive index into low refractive index monomers and high refractive index monomers.

[0187] ---Low refractive index monomer--- The low refractive index monomer has a refractive index of less than 1.5. The low refractive index monomer is not particularly limited and can be appropriately selected depending on the purpose as long as it has a refractive index of less than 1.5 and does not inhibit the dispersibility of the particles, and examples thereof include polyfunctional monomers. Specifically, 1,4-butanediol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol (meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, 3-methylpentanediol di(meth)acrylate, diethylene glycol bis-β-(meth)acryloyloxypropionate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(2-hydroxyethyl)isocyanate di(meth)acrylate, pentaerythritol tetra(meth)acrylate, 2,3-bis(meth)acrylate, ) acryloyloxyethyloxymethyl [2.2.1] heptane, poly 1,2-butadiene di(meth)acrylate, 1,2-bis(meth)acryloyloxymethylhexane, nonaethylene glycol di(meth)acrylate, tetradecane ethylene glycol di(meth)acrylate, 10-decanediol (meth)acrylate, 3,8-bis(meth)acryloyloxymethyl tricyclo [5.2.10] decane, hydrogenated bisphenol A di(meth)acrylate, 2,2-bis (4- (meth) acryloyloxydiethoxyphenyl) propane, 1,4-bis ((meth) acryloyloxymethyl) cyclohexane, hydroxypivalic acid ester neopentyl glycol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, epoxy-modified bisphenol A di(meth)acrylate, etc.

[0188] The low refractive index monomer may contain a polyfunctional fluorine monomer from the viewpoint of reducing the refractive index. The polyfunctional fluorine monomer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include 2,2,2-trifluoroethyl acrylate (refractive index: 1.34), 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, 2-(perfluorodecyl)ethyl (meth)acrylate, α-methyl trifluoromethacrylate, and α-ethyl trifluoromethacrylate.

[0189] ---High refractive index monomer--- The refractive index of the high refractive index monomer is 1.5 or higher. The high refractive index monomer is not particularly limited and can be appropriately selected depending on the purpose as long as the refractive index is 1.5 or higher. Examples of the high refractive index monomer include monomers containing aromatic rings, monomers containing halogen elements other than fluorine, and monomers containing atoms such as S (sulfur), N (nitrogen), or P (phosphorus). Specific examples include styrene, vinyltoluene, vinylnaphthalene, vinylbiphenyl, benzyl methacrylate, bis(4-methacryloylthiophenyl)sulfide, vinylphenyl sulfide, and 4-methacryloxyphenyl-4'-methoxyphenylthioether. These may be used alone or in combination of two or more.

[0190] The molecular weight of the resin is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of good solubility in the solvent and good viscosity of the liquid composition, it is preferably 5,000 or more and less than 500,000.

[0191] The method for measuring the molecular weight of a resin is not particularly limited and can be appropriately selected depending on the purpose. For example, the molecular weight can be measured by gel permeation chromatography (HLC-8320GPC EcoSEC, manufactured by Tosoh Corporation) or MALS (static light scattering using a multi-angle light scattering detector).

[0192] The resin content is not particularly limited and can be selected appropriately depending on the purpose. However, from the viewpoint of achieving good solubility in the solvent and good viscosity of the liquid composition, the resin content is preferably 1% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 30% by mass or less, of the total amount of the liquid composition.

[0193] -Photopolymerization initiator- When a curable resin is used as the resin, it is preferable to use a photopolymerization initiator.

[0194] The photopolymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, but a photoradical polymerization initiator or a photocationic polymerization initiator is preferred, and a photoradical polymerization initiator is more preferred. The curable resin can be cured by irradiation with ionizing radiation in the presence of the photoradical polymerization initiator.

[0195] The photoradical polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfonium compounds, onium salts, borate salts, active halogens, etc. These may be used alone or in combination of two or more.

[0196] The acetophenones are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.

[0197] The benzoins are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include benzoin benzenesulfonate, benzoin toluenesulfonate, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

[0198] The benzophenones are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone, and p-chlorobenzophenone.

[0199] The phosphine oxides are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0200] The photopolymerization initiator may be appropriately synthesized or may be commercially available.The commercially available photopolymerization initiator may be, for example, under the trade name, Irgacure 651, Irgacure 184, Irgacure 819, Irgacure 907, Irgacure 1870 (CGI-403 / Irg184=7 / 3 mixed initiator), Irgacure 500, Irgacure 369, Irgacure 1173, Irgacure 2959, Irgacure 4265, Irgacure 4263, Irgacure 127, OXE01, Lucirin TPO (all manufactured by BASF), Kayacure DETX- S, Kayacure BP-100, Kayacure BDMK, Kayacure CTX, Kayacure BMS, Kayacure 2-EAQ, Kayacure ABQ, Kayacure CPTX, Kayacure EPD, Kayacure ITX, Kayacure QTX, Kayacure BTC, Kayacure MCA (all manufactured by Nippon Kayaku Co., Ltd.), Esacure (KIP100F, KB1, EB3, BP, X33, KTO46, KT37, KIP150, TZT) (manufactured by Sartomer Corporation), and the like.

[0201] The content of the photopolymerization initiator is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoints of improving the curing rate, improving the reaction rate, and minimizing the amount of residual initiator, it is preferably 1% by mass or more and 30% by mass or less based on the total amount of the monomer, oligomer, and polymer.

[0202] -Photosensitizer- The photosensitizer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone, thioxanthone, etc. Furthermore, one or more auxiliary agents such as azide compounds, thiourea compounds, mercapto compounds, etc. may be used in combination.

[0203] The photosensitizer may be a suitably synthesized one or a commercially available product, such as Kayacure (DMBI, EPA) (manufactured by Nippon Kayaku Co., Ltd.).

[0204] -Surfactants- The surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include fluorine surfactants and silicone surfactants.

[0205] -Rheology control agent- The rheology control agent is not particularly limited and can be appropriately selected depending on the purpose.

[0206] -Antioxidants- The antioxidant is not particularly limited and can be appropriately selected depending on the purpose.

[0207] - Antifungal agent - The antifungal agent is not particularly limited and can be appropriately selected depending on the purpose.

[0208] [Physical properties of liquid composition] The viscosity of the liquid composition at 25°C is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 3 mPa·s or more and 1,000 mPa·s or less, and more preferably 5 mPa·s or more and 20 mPa·s or less. When the viscosity of the liquid composition is 3 mPa·s or more, the problem of mist generation from the liquid composition can be eliminated. When the viscosity of the liquid composition at 25°C is 1,000 mPa·s or less, the liquid composition can be ejected using an inkjet head, and the process temperatures in the film formation step and film curing step can be reduced, facilitating leveling and achieving a uniform coating film.

[0209] The method for measuring the viscosity of the liquid composition is not particularly limited and can be selected appropriately depending on the purpose. For example, the viscosity can be measured at 25°C using a rotational viscometer (viscometer TVE-25L, manufactured by Tokyo Glass Instruments Co., Ltd.) or a rheometer (MCR302, manufactured by Anton Paar).

[0210] The surface tension of the liquid composition is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoints of uniformity during film formation, stability when the liquid composition is inkjet-discharged, and storage stability of the liquid composition, it is preferably 10 mN / m or more, more preferably 20 mN / m or more, and preferably 40 mN / m or less, and more preferably 30 mN / m or less. When the surface tension of the liquid composition is 10 mN / m or more, the problem of splitting of discharged droplets can be eliminated. When the surface tension of the liquid composition is 40 mN / m or less, the problem of droplets becoming difficult to level, impairing the uniformity of the coating film, can be eliminated.

[0211] The method for measuring the surface tension of the liquid composition is not particularly limited and can be appropriately selected depending on the purpose. For example, the surface tension can be measured using a surface tensiometer (DY-300, manufactured by Kyowa Interface Science Co., Ltd.).

[0212] <<Film curing process>> The film hardening step is a step of hardening the film. The film hardening step can be suitably carried out by a film hardening means.

[0213] The method for curing the film is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include natural drying, heat drying, vacuum drying, ultraviolet (UV) curing, heat curing, infrared curing, electron beam curing, two-component curing, solid-liquid separation curing, etc. Examples of film curing means that can be used include a hot plate, a reduced pressure dryer, and a UV light.

[0214] There are no particular restrictions on the curing conditions for UV curing, but the illuminance should be 1,500 mW / cm 2 More than 5,000mW / cm 2 and the cumulative light intensity is 1,000 mJ / cm 2 More than 5,000mmJ / cm 2 It is preferable that:

[0215] The temperature setting in the film curing step is not particularly limited and can be set appropriately depending on the purpose, but it is preferably equal to or lower than the glass transition temperature of the resin contained in the liquid composition and equal to or higher than the boiling point of the solvent contained in the liquid composition. When the temperature setting is within these ranges, the problem of changes in the physical properties of the obtained optical functional layer can be eliminated.

[0216] The humidity in the film curing step is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 30% or less. If the humidity is 30% or less, problems such as a change in the curing speed and deterioration of the optical function due to moisture in the film can be suppressed.

[0217] Curing is a chemical film formation process in which resins and the like are fused and solidified, while drying is a physical film formation process in which a solid material is solidified by volatilizing a solvent. Drying and curing may occur simultaneously depending on the composition of the liquid composition. When drying and curing occur simultaneously, the cured state of the liquid composition can also be evaluated by the amount of evaporation of the solvent in the liquid composition.

[0218] In this specification, a state in which the liquid composition is 100% cured is referred to as a "100% cured state." In other words, a 100% cured state is a state in which the solvent in the liquid composition has completely evaporated (i.e., 100% by mass), or a state in which the energy required for complete curing has been applied. Therefore, for example, a "50% cured state" is a state in which 50% by mass of the solvent in the liquid composition has evaporated, or a state in which the energy required for 50% curing has been applied. On the other hand, a state in which the liquid composition is not cured (a 0% cured state) is referred to as a "0% cured state."

[0219] The time for which the film hardening process is carried out is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of distributing particles at the interface between adjacent layer regions, it is preferable that the time be such that the hardening state is 30% or more and 100% or less.

[0220] Therefore, the film hardening step may include hardening the liquid composition to any desired degree. For convenience, "hardening the liquid composition to any desired degree" may be referred to as "semi-hardening."

[0221] When liquid compositions are ejected by inkjet, the state of hardening of droplets of one liquid composition adjacent to droplets of another liquid composition ejected can be controlled by undergoing semi-hardening, and an optically functional film with a more gradual change in refractive index can be obtained.

[0222] The "any degree" of semi-curing is not particularly limited and can be appropriately selected depending on the application of the optical component. For example, the cured state of the liquid composition can be 30% or more but less than 100%, preferably 30% or more but 95% or less. When it is desired to control the refractive index difference between adjacent layer regions in the optical functional layer to be small, the cured state of the liquid composition may be 30% or more but 70% or less.

[0223] The curing state of the droplets can be controlled by measuring in advance the relationship between the curing state of the liquid composition used and the amount of energy applied using the above-mentioned measurement method. For example, when drying and curing proceed simultaneously, the curing state of the droplets can be controlled by measuring in advance the relationship between the curing state of the liquid composition used and the amount of evaporation.

[0224] For example, in the nth film curing step, the liquid composition for producing the nth layer region is semi-cured, and in the n+1th film formation step, the semi-cured nth film and the liquid composition for producing the n+1th layer region are simultaneously brought to a 100% cured state, thereby making it possible to control the curing state of multiple adjacent layer regions and to more gradually change the refractive index in the thickness direction of the optical functional layer.

[0225] Furthermore, when the film formation process includes forming a printing pattern, in the nth film curing process, one liquid composition for producing the nth layer region, for example, high refractive index liquid composition 42, is semi-cured, and in the (n+1)th film formation process, high refractive index liquid composition 42 and another liquid composition for producing the nth layer region, which has a different refractive index from high refractive index liquid composition 42, for example, low refractive index liquid composition 41, are simultaneously brought to a 100% cured state.This makes it possible to control the curing state of adjacent droplets with different refractive indexes within one layer region, and to obtain an optical functional layer with a more gradual change in refractive index within one layer region.

[0226] The method for confirming the curing state of each layer region is not particularly limited and can be selected appropriately depending on the application of the optical component. For example, measurements can be made by calculating the relationship between height change, weight change, refractive index change, and hardness change using a laser displacement meter, and time change using a rigid pendulum physical property tester (RPT-3000W, manufactured by AND Co.), and the elasticity and viscosity of the film.

[0227] Depending on the curing state of each layer region, applying a liquid composition containing particles onto a layer region that does not contain particles may cause the interface to re-dissolve and the particles to migrate into the interior of that layer region.

[0228] When the film curing method is UV curing, the light source is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a high-pressure mercury lamp (LightHammer6, manufactured by Heraeus) and an LED (manufactured by Heraeus) that emits light in the range of 360 nm to 400 nm. UV irradiation may be performed under a nitrogen atmosphere. The light intensity of the light source is not particularly limited and can be appropriately set depending on the purpose, and can be, for example, 0.5 W / cm. 2 (Integrated light intensity: 500mJ / cm 2 ~3,000mJ / cm 2 ) can be set to

[0229] When the film curing method is thermal curing, the heating temperature is not particularly limited and can be appropriately selected depending on the purpose and the softening point of the substrate to be used. For example, from the viewpoint of the activation energy of the crosslinking agent contained in the liquid composition and safety during curing, a heating temperature of 70°C or higher and 200°C or lower is preferred.

[0230] When the film is cured by heat, the heating time is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of film curability and productivity, it is preferably 0.5 minutes or more and 10 minutes or less. A hot plate or the like can be used for heating.

[0231] [Figures 5A to 6B] Here, the film formation process includes forming a print pattern, and controlling the hardening state of adjacent droplets with different refractive indices within one layer region will be specifically described with reference to FIGS. 5A to 6B.

[0232] Fig. 5A is a schematic side view showing a process of ejecting droplets of a low-refractive-index liquid composition 41 from a second inkjet head onto an optical functional layer formed by droplets of a high-refractive-index liquid composition 42 in a 100% cured state ejected from a first inkjet head and curing the droplets. Fig. 5B is a schematic side view showing a process of ejecting droplets of a low-refractive-index liquid composition 41 from a second inkjet head onto an optical functional layer formed by droplets of a high-refractive-index liquid composition 42 in a 50% cured state ejected from the first inkjet head and curing the droplets.

[0233] Here, we will assume that an optical component having a single optical functional layer is manufactured using two liquid compositions: a high-refractive index liquid composition 42 that has a relatively high refractive index after curing, and a low-refractive index liquid composition 41 that has a relatively low refractive index after curing. First, the high-refractive index liquid composition 42 is dispensed onto the substrate 1 and subjected to the optical functional layer formation process, resulting in a 100% cured state. The cured product of the high-refractive index liquid composition 42 is designated as a cured product 42a. Next, the low-refractive index liquid composition 41 is dispensed onto the cured product 42a, and droplets of the low-refractive index liquid composition 41 are disposed on the substrate 1. The cured product of the low-refractive index liquid composition 41 obtained by curing the low-refractive index liquid composition 41 to a 100% cured state is designated as a cured product 41a. After curing, an interface 43 is formed between the cured product 42a and the cured product 41a (see FIG. 5A).

[0234] Meanwhile, the high-refractive index liquid composition 42 dispensed onto the substrate 1 is subjected to a semi-curing process, for example, until it is 50% cured. The semi-cured product of the high-refractive index liquid composition 42 is formed into a cured product 22b. Next, when the low-refractive index liquid composition 41 is dispensed onto the semi-cured product 42b, droplets of the low-refractive index liquid composition 41 are disposed on the substrate 1 between the semi-cured product 42b. At this time, the interface between the semi-cured product 42b and the droplets of the low-refractive index liquid composition 41 is corroded. This is further cured to make the semi-cured product 42b and the low-refractive index liquid composition 41 100% cured. As a result, the semi-cured product 42b becomes a cured product 42a. Furthermore, the 100% cured cured product of the low-refractive index liquid composition 41 is formed into a cured product 41a. As a result, an interface 43 is not formed, and the refractive index changes gradually between the cured product 41a and the cured product 42a. As a result, the refractive index in the in-plane direction of the optical functional layer changes (see FIG. 5B).

[0235] In this way, when forming a printing pattern so that the refractive index changes in a direction intersecting the thickness direction of the substrate 1, an optical functional layer in which the refractive index in the plane direction changes more gradually can be obtained by controlling the curing state of droplets of at least two liquid compositions with different refractive indices that are adjacent in a direction intersecting the thickness direction of the substrate 1 to an arbitrary degree.

[0236] Fig. 6A is a schematic side view showing a process of discharging and curing droplets of a low-refractive-index liquid composition 41 for a second layer onto a first optical functional layer that is in a 100% cured state. Fig. 6B is a schematic side view showing a process of discharging and curing droplets of a low-refractive-index liquid composition 41 for a second layer onto a first optical functional layer that is in a 50% cured state.

[0237] Here, we assume that an optical component having two optically functional layers is manufactured using two liquid compositions: a high-refractive-index liquid composition 42 that has a relatively high refractive index after curing, and a low-refractive-index liquid composition 41 that has a relatively low refractive index after curing. First, the high-refractive-index liquid composition 42 is dispensed onto the substrate 1 and subjected to the optically functional layer formation process to reach a 100% cured state. The cured product of the high-refractive-index liquid composition 42 is designated as a cured product 42a. Next, the low-refractive-index liquid composition 41 is dispensed onto the cured product 42a, and droplets of the low-refractive-index liquid composition 41 are placed on the cured product 42a. The cured product of the low-refractive-index liquid composition 41 obtained by curing the low-refractive-index liquid composition 41 to reach a 100% cured state is designated as a cured product 41a. After curing, an interface 43 is formed between the cured product 42a of the first layer and the cured product 41a of the second layer (see FIG. 6A).

[0238] Meanwhile, the high-refractive index liquid composition 42 dispensed onto the substrate 1 is subjected to a semi-curing process, for example, until it is 50% cured. The semi-cured product of the high-refractive index liquid composition 42 is formed into a cured product 22b. Next, the low-refractive index liquid composition 41 is dispensed onto the semi-cured product 42b, and droplets of the low-refractive index liquid composition 41 are disposed on the semi-cured product 42b. At this time, the interface between the semi-cured product 42b and the droplets of the low-refractive index liquid composition 41 is corroded. This is further cured to make the semi-cured product 42b and the low-refractive index liquid composition 41 100% cured. As a result, the semi-cured product 42b becomes a cured product 42a. Furthermore, the 100% cured cured product of the low-refractive index liquid composition 41 is formed into a cured product 41a. As a result, an interface 43 is not formed, and the refractive index changes gradually between the cured products 41a and 42a. As a result, the refractive index in the stacking direction of the optical functional layer changes (see FIG. 6B).

[0239] In this way, when forming a printing pattern so that the refractive index changes in the thickness direction of the substrate 1, an optical functional layer in which the refractive index changes more gradually in the thickness direction can be obtained by controlling the curing state of at least two droplets of liquid composition with different refractive indices that are adjacent in the thickness direction of the substrate 1 to an arbitrary degree.

[0240] An optical member having a printed pattern in which the refractive index changes in the thickness direction of the substrate 1 can be suitably used as an anti-reflection film.

[0241] <Optical functional layer formation process> The optical function layer forming step is a step of forming an optical function layer having a uniform thickness by repeating a film forming step and a film curing step. The optical function layer forming means includes a film forming means and a film curing means. The optical function layer forming step can be suitably performed by the optical function layer forming means.

[0242] As described above, the optical functional layer has a refractive index that varies at least in the thickness direction. More specifically, when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the difference in refractive index between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. Furthermore, it is preferable that the optical functional layer further has a refractive index that varies in the plane direction.

[0243] The optical functional layer forming step includes two or more film forming steps in which the particle content ratios of the liquid compositions are different so that when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. The liquid compositions with different particle content ratios are preferably a combination of liquid compositions that result in a refractive index difference between the liquid compositions after curing that is greater than 0 and not greater than 0.1. This ensures that when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions falls within a preferred range.

[0244] The optical functional layer forming step includes two or more film forming steps in which the particle content ratio of the liquid composition is different, which results in regions in the optical functional layer having different particle content ratios, and when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction, an optical functional layer can be formed in which the difference in refractive index between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1.

[0245] In the optical functional layer forming process, it is not necessary to change the particle content ratio of the liquid composition each time the film forming process is performed. For example, when the optical functional layer is formed by repeating the film forming process and the film curing process three times each, the first and second film forming processes may use the same liquid composition to form the film, and the third film forming process may use a liquid composition having a different particle content ratio from the liquid composition used in the first and second film forming processes. Here, an optical functional layer forming process having three film forming processes and three film curing processes each is exemplified, but in the case of an optical functional layer forming process having four or more film forming processes and four or more film curing processes each, it is also not necessary to change the particle content ratio contained in the liquid composition each time the film forming process is performed.

[0246] In the optical function layer forming step, it is preferable to change the particle content ratio in the liquid composition each time the film forming step is performed, which allows the refractive index to be gradually changed from the layer region in contact with the substrate to the layer region of the outermost surface of the optical function layer, thereby suppressing the influence of interfacial reflection between each layer region.

[0247] In the optical functional layer forming process, where n is a natural number, the particle content of the liquid composition used in the (n+1)th film forming process is preferably smaller than or equal to the particle content of the liquid composition used in the nth film forming process, and more preferably the particle content of the liquid composition used in the (n+1)th film forming process is smaller than the particle content of the liquid composition used in the nth film forming process. This allows for the formation of an optical functional layer in which the particle content decreases from the layer region in contact with the substrate toward the outermost layer region of the optical functional layer. Alternatively, in the optical functional layer forming process, where n is a natural number, the particle content of the liquid composition used in the (n+1)th film forming process is preferably larger than or equal to the particle content of the liquid composition used in the nth film forming process, and more preferably the particle content of the liquid composition used in the (n+1)th film forming process is larger than the particle content of the liquid composition used in the nth film forming process. This allows for the formation of an optical functional layer in which the particle content increases from the layer region in contact with the substrate toward the outermost layer region of the optical functional layer.

[0248] The method for producing an optical member of the present invention is preferably carried out in an environment at room temperature (25° C.) and a humidity of 20% to 30%, although this depends on the physical properties of the liquid composition used.

[0249] The structures of the optical components obtained by the method for producing optical components of the present invention can be confirmed, for example, by cooling them using an ion milling device IM4000 (manufactured by Hitachi High-Technologies Corporation) and observing the surface and cross section of the optical component using a Gemini300 heated cathode field-effect scanning electron microscope (Schottky FE-SEM).

[0250] [Application] The optical member of the present invention can be suitably used as an anti-reflection film, a light diffusing film, a reflection-enhancing film, or the like. [Example]

[0251] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0252] [Preparation of Liquid Composition] <Preparation of Low Refractive Index Liquid Composition A-1> The materials used are as follows: PMMA and PGME were stirred at 60° C. for 2 hours, and then stirred at 25° C. for 8 hours. The mixture was then filtered through a 2 μm filter to prepare low refractive index liquid composition A-1. -material- PMMA (polymethyl methacrylate, Sigma-Aldrich): 2.0 g PGME (propylene glycol monomethyl ether, manufactured by Kanto Chemical Co., Ltd.): 98.0 g

[0253] <Preparation of Low Refractive Index Liquid Composition A-2> A low refractive index liquid composition A-2 was prepared in the same manner as the low refractive index liquid composition A-1, except that the materials were changed as follows. -material- PNB (Polynorbornene, manufactured by Sumitomo Bakelite Co., Ltd.): 2.0g PGME (propylene glycol monomethyl ether, manufactured by Kanto Chemical Co., Ltd.): 98.0 g

[0254] <Preparation of Low Refractive Index Liquid Composition A-3> The materials used are as follows: HFMA and PGME were stirred at 40° C. for 2 hours, and then stirred at 25° C. for 8 hours. The mixture was then filtered through a 2 μm filter to prepare low refractive index liquid composition A-3. -material- ·HFMA (1,1,1,3,3,3-Hexafluoroisopropyl Methacrylate, manufactured by Sigma-Aldrich): 2.0g PGME (propylene glycol monomethyl ether, manufactured by Kanto Chemical Co., Ltd.): 98.0 g

[0255] <Preparation of Low Refractive Index Liquid Composition A-4> The materials used were as follows: Urethane acrylate and PGME were stirred at room temperature for 1 hour, and then hollow silica particles were added and stirred at 25° C. for 8 hours. The mixture was then filtered through a 2 μm filter to prepare low refractive index liquid composition A-4. -material- Hollow silica particles (dispersion with 20% solid content, average primary particle diameter: 70 nm): 1.6 g Urethane acrylate (Mitsubishi Chemical Corporation): 4.6g PGME (propylene glycol monomethyl ether, manufactured by Kanto Chemical Co., Ltd.): 308.7g Photoinitiator: Irgacure 184: 0.1g

[0256] <Preparation of Low Refractive Index Liquid Composition A-5> A low refractive index liquid composition A-5 was prepared in the same manner as the low refractive index liquid composition A-4, except that the blending amounts were changed as follows. -material- Hollow silica particles (dispersion with 20% solid content, average primary particle diameter: 70 nm): 4.7 g Urethane acrylate (Mitsubishi Chemical Corporation): 4.0g PGME (propylene glycol monomethyl ether, manufactured by Kanto Chemical Co., Ltd.): 431.2g Photoinitiator: Irgacure 184: 0.1g

[0257] <Preparation of Low Refractive Index Liquid Composition A-6> A low refractive index liquid composition A-6 was prepared in the same manner as for the low refractive index liquid composition A-4, except that the materials were changed as follows. -material- Hollow silica particles (dispersion with 20% solid content, average primary particle diameter: 70 nm): 12.5 g Urethane acrylate (Mitsubishi Chemical Corporation): 2.4g PGME (propylene glycol monomethyl ether, manufactured by Kanto Chemical Co., Ltd.): 735.0 g Photoinitiator: Irgacure 184: 0.1g

[0258] <Preparation of Low Refractive Index Liquid Composition A-7> The materials used were as follows: Urethane acrylate and PGMEA were stirred at room temperature for 1 hour, and then hollow silica particles were added and stirred at 25° C. for 8 hours. The mixture was then filtered through a 2 μm filter to prepare low refractive index liquid composition A-7. -material- Hollow silica particles (dispersion with 20% solid content, average primary particle diameter: 80 nm): 1.6 g Urethane acrylate (Mitsubishi Chemical Corporation): 4.6g PGMEA (propylene glycol monomethyl ether acetate, manufactured by Kanto Chemical Co., Ltd.): 308.7g Photoinitiator: Irgacure 184: 0.1g

[0259] <Preparation of Low Refractive Index Liquid Composition A-8> A low refractive index liquid composition A-8 was prepared in the same manner as for the low refractive index liquid composition A-7, except that the materials were changed as follows. -material- Hollow silica particles (dispersion of 20% solids by mass, average primary particle diameter: 80 nm): 12.5 g Urethane acrylate (Mitsubishi Chemical Corporation): 2.4g PGMEA (propylene glycol monomethyl ether acetate, manufactured by Kanto Chemical Co., Ltd.): 735.0 g Photoinitiator: Irgacure 184: 0.1g

[0260] <Preparation of Low Refractive Index Liquid Composition A-9> The materials used were as follows: A fluorine-containing acrylate monomer and PGMEA were stirred at room temperature for 1 hour, and then hollow silica particles were added and stirred at 25° C. for 8 hours. The mixture was then filtered through a 2 μm filter to prepare low refractive index liquid composition A-9. -material- Hollow silica particles (dispersion of 20% solids by mass, average primary particle diameter: 80 nm) 12.5 g Fluorine-containing acrylate monomer (2,2,2-trifluoroethyl acrylate, Osaka Organic Chemical Industry Ltd.): 2.4 g PGMEA (propylene glycol monomethyl ether acetate, manufactured by Kanto Chemical Co., Ltd.): 735.0 g Photoinitiator: Irgacure 184: 0.1g

[0261] <Preparation of High Refractive Index Liquid Composition B-1> The materials used are as follows: PS and anisole were stirred for 8 hours at 25° C. After that, the mixture was filtered through a 2 μm filter to prepare high refractive index liquid composition B-1. -material- PS (polystyrene, manufactured by Tosoh Corporation): 2.0 g Anisole (Kanto Chemical Co., Ltd.): 98.0g

[0262] <Preparation of High Refractive Index Liquid Composition B-2> The materials used were as follows: Zirconia nanoparticles and MEK were mixed and stirred at 25°C for 2 hours. PETA and Irgacure 184 were added to the mixture. The mixture was then filtered through a 2 μm filter to prepare high refractive index liquid composition B-2. -material- Zirconia nanoparticles (average primary particle diameter: 11 nm, manufactured by Nippon Shokubai Co., Ltd.): 4.0 g MEK (methyl ethyl ketone, manufactured by Kanto Chemical Co., Ltd.): 553.7g PETA (pentaerythritol triacrylate, Sigma-Aldrich): 7.2g Photoinitiator: Irgacure 184: 0.1g

[0263] <Preparation of High Refractive Index Liquid Composition B-3> High refractive index liquid composition B-3 was prepared in the same manner as high refractive index liquid composition B-2, except that the materials were changed as follows. -material- Zirconia nanoparticles (average primary particle size: 11 nm, manufactured by Nippon Shokubai Co., Ltd.): 4.4 g MEK (methyl ethyl ketone, manufactured by Kanto Chemical Co., Ltd.): 558.6g PETA (pentaerythritol triacrylate, Sigma-Aldrich): 6.9g Photoinitiator: Irgacure 184: 0.1g

[0264] <Preparation of High Refractive Index Liquid Composition B-4> High refractive index liquid composition B-4 was prepared in the same manner as high refractive index liquid composition B-2, except that the materials were changed as follows. -material- Zirconia nanoparticles (average primary particle size: 11 nm, manufactured by Nippon Shokubai Co., Ltd.): 9.4 g MEK (methyl ethyl ketone, manufactured by Kanto Chemical Co., Ltd.): 632.1 g PETA (pentaerythritol triacrylate, Sigma-Aldrich): 3.4g Photoinitiator: Irgacure 184: 0.1g

[0265] The compositions of these liquid compositions are summarized in Tables 1 and 2. Tables 1 and 2 also show the refractive indices of the liquid compositions measured by the following method.

[0266] [Measurement of refractive index of liquid composition] A 4 cm x 4 cm glass plate (alkali-free Eagle XG, manufactured by Hiraoka Special Glass Manufacturing Co., Ltd.) was prepared and cleaned with acetone in an ultrasonic cleaner. After that, it was irradiated with a low-pressure mercury lamp (UV wavelengths 254 nm, 185 nm) from a distance of 30 mm at an illuminance of 3.7 mW / cm using a UV-ozone cleaner (manufactured by Fligen, UV253E). 2The glass substrate was then treated with UV irradiation at 100°C for 10 minutes. A 1.0 wt% aqueous solution of a silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) was then applied to a glass plate, rinsed with pure water, and heated at 100°C for 10 minutes to produce a glass substrate. Each liquid composition was applied to the glass substrate by spin coating to a film thickness of 100 nm, producing a film. To suppress rear surface reflection of the glass substrate, Scotch tape was applied to the glass substrate on the side on which the film was not formed, and the refractive index was measured using a spectroscopic ellipsometer M-2000 (manufactured by JA Woollam Japan). The measurement conditions were as follows: -Measurement conditions- Light source: D2 lamp and QTH lamp Wavelength range: 190nm~1680nm Accumulation time: 10 seconds ·Incidence angle: 50°, 60°, 70°, 80°

[0267] [Table 1]

[0268] [Table 2]

[0269] [Preparation of the substrate] A 4 cm x 4 cm glass plate (alkali-free Eagle XG, manufactured by Hiraoka Special Glass Manufacturing Co., Ltd.) was prepared and cleaned with acetone in an ultrasonic cleaner. After that, it was irradiated with a low-pressure mercury lamp (UV wavelengths 254 nm, 185 nm) from a distance of 30 mm at an illuminance of 3.7 mW / cm using a UV-ozone cleaner (manufactured by Fligen, UV253E). 2 The glass plate was then coated with a 1.0 wt % aqueous solution of a silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), rinsed with pure water, and heated at 100°C for 10 minutes to produce a glass substrate.

[0270] [Fabrication of optical components] Each liquid composition was applied in turn onto a glass substrate by spin coating or inkjet printing, and then cured to produce an optical functional layer. When the resin contained in the liquid composition was a non-curable resin, the liquid composition was applied and then cured by heating and drying at a temperature of 40°C for 1 hour to produce an optical functional layer. When the resin contained in the liquid composition was a curable resin, the liquid composition was applied and then cured using a UV curing method to produce an optical functional layer. Using the above methods, an optical component having an optical functional layer on a glass substrate was produced. The application conditions for each liquid composition using spin coating and inkjet printing were set as follows:

[0271] -Spin coating method- The liquid composition was dropped onto the glass substrate using a spin coater (1H-DX, manufactured by Mikasa Co., Ltd.), and coated at a rotation speed of 3000 rpm for 30 seconds.

[0272] -Inkjet method- The liquid composition was applied onto the glass substrate using a printing device (manufactured by Genesis Co., Ltd.) equipped with an inkjet head (manufactured by Ricoh Co., Ltd., "MH5420").

[0273] An ink tank and an inkjet head were prepared for each type of liquid composition to be applied, and each was connected by a tube. Then, each ink tank was filled with each liquid composition. For example, when three types of liquid compositions were to be applied, the three types of liquid compositions were filled into ink tank 1, ink tank 2, and ink tank 3, respectively. Similarly, each liquid composition was supplied to the corresponding head (head 1, head 2, and head 3). For example, when five types of liquid compositions were to be applied, the five types of liquid compositions were filled into ink tank 1, ink tank 2, ink tank 3, ink tank 4, and ink tank 5, respectively. Similarly, each liquid composition was supplied to the corresponding head (head 1, head 2, head 3, head 4, and head 5), respectively.

[0274] When three types of liquid compositions were to be applied, head 1, head 2, and head 3 were arranged side by side in the head scanning direction. Following the scanning of head 1, head 2 was set to follow along the same path. Similarly, following the scanning of head 2, head 3 was set to follow along the same path. This constitutes one scan.

[0275] When there were five types of liquid compositions to be applied, head 1, head 2, head 3, head 4, and head 5 were arranged in the head scanning direction. Following the scanning of head 1, head 2 was set to follow along the same path. Similarly, following the scanning of head 2, head 3 was set to follow along the same path. Similarly, following the scanning of head 3, head 4 was set to follow along the same path. Similarly, following the scanning of head 4, head 5 was set to follow along the same path. This constitutes one scan.

[0276] The printing conditions were a droplet volume of 10 pL, a resolution of 600 dpi × 600 dpi, and a table transport speed of 45 mm / s, all adjusted by applying voltage. The stage temperature of the printing device was set to 40°C. The ejection data obtained at this time is shown in Figure 7. Each pixel in the ejection data corresponds to one droplet ejected from one nozzle of the head. The ejection data also includes two-dimensional numerical data (numbers greater than or equal to 1) for each pixel. In Figure 7, each pixel is represented by a square, and the numbers within the squares represent the numerical data for the two-dimensional data. While the numerical data can be set as desired, in this example, "0" represents no ejection and "1" represents ejection. The droplet volume was adjusted by applying voltage or pressure. Droplets were applied to all pixels at once using a single-pass method.

[0277] (Examples 1 to 12 and Comparative Examples 1 to 9) Based on [Preparation of Optical Members], optical members were prepared using the combinations of liquid compositions shown in Tables 3 to 7. In Tables 3 to 7, "first discharge" indicates discharge from head 1, "second discharge" indicates discharge from head 2, "third discharge" indicates discharge from head 3, "fourth discharge" indicates discharge from head 4, and "fifth discharge" indicates discharge from head 5. Each discharge was set so that the thickness of the optical functional layer after curing would be 100 nm. For example, in Example 1, liquid composition A-4 was discharged in the first discharge so that the thickness of the optical functional layer after curing would be 100 nm, liquid composition A-7 was discharged in the second discharge so that the thickness of the optical functional layer after curing would be 100 nm, and liquid composition A-4 was discharged in the third discharge so that the thickness of the optical functional layer after curing would be 100 nm.

[0278] (Comparative Example 10) A commercially available mosmite film (product name: Moth-eye type anti-reflection film Mosmite, manufactured by Mitsubishi Chemical Corporation, BA080M2C, SRF type PET base) was obtained. This film was attached to a glass substrate to produce an optical member of Comparative Example 10. Note that there was no difference in refractive index in the thickness direction of the mosmite film as measured according to the "Measurement of refractive index of optical functional layer" below.

[0279] The optical members of Examples 1 to 24 and Comparative Examples 1 and 2 were subjected to the following measurements and evaluations.

[0280] [Measurement of refractive index of optical functional layer] To suppress rear surface reflection of the glass substrate, Scotch tape was applied, and the refractive index difference between the layer regions was measured using a spectroscopic ellipsometer M-2000 (manufactured by JA Woollam Japan), and evaluated based on the following evaluation criteria. The measurement conditions were as follows. The results are shown in Tables 3 to 7. The layer regions were divided evenly at 100 nm intervals from the interface between the glass substrate and the optical functional layer in the thickness direction of the optical functional layer. -Measurement conditions- Light source: D2 lamp and QTH lamp Wavelength range: 190nm~1680nm Accumulation time: 10 seconds ·Incidence angle: 50°, 60°, 70°, 80° -Evaluation criteria- A: The refractive index difference between the layer regions is greater than 0 and 0.1 or less B: The refractive index difference between the layer regions is 0 or exceeds 0.1

[0281] [Measurement of the film thickness of the optical functional layer] A groove was made on the surface of the optical functional layer with a cutter, and the film thickness was measured with a stylus-type step film thickness meter (Alpha-Step D-500, manufactured by ULVAC, Inc.). The results are shown in Tables 3 to 7.

[0282] [Evaluation of average reflectance of optical components] To suppress reflection from the rear surface of the glass substrate, it was painted black with a black spray (matt black aspen lacquer spray), and black construction paper was placed on the rear surface of the glass substrate. The incident angle was set to 5°, and the reflectance of the optical component was evaluated using a spectrophotometer (V-770, manufactured by JASCO Corporation). The measurement conditions were as follows. The average reflectance [%] in the visible range was calculated from the obtained reflection spectrum. The results are shown in Tables 3 to 7. -Measurement conditions- Measurement range: 780nm to 380nm (visible light range) Data capture interval: 0.5 nm UV / Vis Bandwidth: 5.0nm NIR bandwidth: 20.0nm UV / Vis response: 0.24 seconds NIR response: 0.24 seconds Scanning mode: Continuous Scanning speed: 200nm / min ·Light source switching: 340nm Diffraction grating switching: 850nm ·Light source: D2 / WI Filter switching: Step Correction: Baseline / Dark

[0283] [Evaluation of wavelength dependence of optical components] The maximum and minimum reflectances of the optical components in visible light were measured using the same method as in the evaluation of the average reflectance. Wavelength dependency was calculated from the absolute value ΔR of the difference between the maximum and minimum reflectances. Wavelength dependency of 5% or less was considered feasible. The results are shown in Tables 2 to 7.

[0284] [Evaluation of average transmittance of optical components] The incident angle was set to 0°, and the average transmittance of the optical member was evaluated using a spectrophotometer (V-770, manufactured by JASCO Corporation). The measurement conditions were as follows. The results are shown in Tables 3 to 7. -Measurement conditions- Measurement range: 780nm~380nm Data capture interval: 0.5 nm UV / Vis Bandwidth: 5.0nm NIR bandwidth: 20.0nm UV / Vis response: 0.24 seconds NIR response: 0.24 seconds Scanning mode: Continuous Scanning speed: 200nm / min ·Light source switching: 340nm Diffraction grating switching: 850nm ·Light source: D2 / WI Filter switching: Step Correction: Baseline / Dark

[0285] [Evaluation of haze value of optical components] The haze value of the optical member was measured using a haze meter (NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS-K-7136:2000 (ISO 14782:1999), including the glass substrate as the base material. The haze value of the glass substrate alone was 0.23%. The results are shown in Tables 3 to 7.

[0286] [Evaluation of film strength of optical functional layer] To evaluate the film strength of the optical functional layer, a scratch resistance test and an adhesion test were carried out.

[0287] <Scratch resistance test> The optical element was placed on a flat table with the surface having the optical function layer facing up, and was then placed on #0000 steel wool at a depth of 2.5 cm. 2 The surface of the optical functional layer of the optical component was rubbed back and forth 10 times with a load of 200 g per rubbed area, and scratches occurring within a 2 cm area perpendicular to the rubbing direction were visually observed. Evaluation was based on the following evaluation criteria. The results are shown in Tables 3 to 7. -Evaluation criteria- A: There are no scratches and no problems with the product. B: There are some scratches, but there is no problem with the product. C: There are many scratches and there are problems with the product.

[0288] <Adhesion test> Using a cutter, 11 cuts measuring 1 mm in length and width were made in the optical functional layer to create 100 1 mm squares (cross-cuts), and tape (Nitto Denko Cellophane Tape No. 29) was applied on top of them. The surface was then rubbed back and forth 10 times with a spatula, and the tape was then forcefully peeled off. This process was repeated three times, and the degree of film peeling was visually observed. Evaluation was performed based on the following evaluation criteria. The results are shown in Tables 3 to 7. -Evaluation criteria- A: There is no peeling at all and there are no problems with the product. B: There is slight peeling, but it does not affect the product. C: There is a lot of peeling and there is a problem with the product.

[0289] [Table 3]

[0290] [Table 4]

[0291] [Table 5]

[0292] [Table 6]

[0293] [Table 7]

[0294] The present invention includes, for example, the following aspects. <1> a substrate; an optically functional layer containing particles and having a uniform thickness on the substrate; An optical element having This optical component is characterized in that when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. <2> The refractive index of each layer region of the optical functional layer is 1.0 or more and 2.5 or less. <1> 1. The optical member according to claim 1. <3> the refractive index of the optical functional layer increases from the layer region in contact with the base toward the layer region of the outermost layer of the optical functional layer; <1> or <2> 1. The optical member according to claim 1. <4> the refractive index of the optical functional layer decreases from the layer region in contact with the base toward the layer region of the outermost layer of the optical functional layer; <1> or <2> 1. The optical member according to claim 1. <5> the optical functional layer contains one type of particle, The optical functional layer has a particle content ratio different from each other in the pair of adjacent layer regions. <1> from <4> 10. The optical member according to claim 9, wherein the first and second electrodes are arranged parallel to each other. <6> the optical functional layer contains at least two types of particles having different refractive indices, The optical functional layer has a different content ratio of the at least two kinds of particles having different refractive indexes in the pair of adjacent layer regions. <1> from <4> 10. The optical member according to claim 9, wherein the first and second electrodes are arranged parallel to each other. <7> The particles include at least one selected from the group consisting of polymer particles, silica particles, and oxide particles. <1> from <6> 10. The optical member according to claim 9, wherein the first and second electrodes are arranged parallel to each other. <8> The difference between the maximum reflectance of the optical element in the visible region measured at an incident angle of 5° and the minimum reflectance of the optical element in the visible region measured at an incident angle of 5° is 5% or less. <1> from <7> 10. The optical member according to claim 9, wherein the first and second electrodes are arranged parallel to each other. <9> The optical functional layer is such that all of the layer regions contain the particles. <1> from <8> 10. The optical member according to claim 9, wherein the first and second electrodes are arranged parallel to each other. <10> the optical function layer has regions with different refractive indices in a surface direction of the optical function layer; <1> from <9> 10. The optical member according to claim 9, wherein the first and second electrodes are arranged parallel to each other. <11> a film forming step of discharging a liquid composition containing particles onto a substrate to form a film; a film hardening step of hardening the film; an optical function layer forming step of repeating the film forming step and the film curing step to form an optical function layer having a uniform thickness; Including, This is a method for manufacturing an optical element, characterized in that the optical functional layer forming step includes two or more film forming steps in which the content ratio of the particles contained in the liquid composition is different so that when the optical functional layer is divided into a plurality of layer regions every 100 nm from the interface between the base and the optical functional layer in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.1. <12> the film forming step includes ejecting at least two liquid compositions having different refractive indices onto the substrate by an inkjet method to form a print pattern in a direction intersecting a thickness direction of the substrate, forming the print pattern by ejecting one liquid composition so that the one liquid composition and another liquid composition having a refractive index different from that of the one liquid composition are adjacent to each other in a direction intersecting the thickness direction of the substrate; <11> 1. A method for producing the optical member according to claim 1. <13> forming the print pattern by discharging the at least two liquid compositions having different refractive indices so that the refractive indexes change in at least one direction intersecting with the thickness direction of the substrate; <12> 1. A method for producing the optical member according to claim 1. <14> the film forming step comprises discharging the at least two liquid compositions having different refractive indices while changing the discharge amounts of each of the liquid compositions; <11> from <13> 10. A method for producing an optical member according to any one of the above items. <15> The film hardening step includes hardening the liquid composition to a desired degree. <11> from <14> 10. A method for producing an optical member according to any one of the above items.

[0295] The aforementioned <1> From the above <10> The optical member according to any one of the above items, <11> From the above <15> According to any one of the methods for producing an optical member described above, the various problems in the prior art can be solved and the object of the present invention can be achieved. [Explanation of symbols]

[0296] 1 Base 20 Optical functional layer 21 First Layer Region 22 Second Layer Region 23 Third Layer Area 24 Fourth Layer Region 25 Fifth Layer Area 26 Sixth Layer Area 27 Seventh Layer Realm 31 particles 32 Resin 41 Low refractive index liquid composition 42 High refractive index liquid composition 101 Optical components 102 Optical components 103 Optical Components X1 center X2 center [Prior art documents] [Patent documents]

[0297] [Patent Document 1] Patent No. 6396003

Claims

1. a substrate; an optically functional layer containing particles and having a uniform thickness on the substrate; An optical element having An optical component characterized in that, when the optical functional layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and less than 0.

1.

2. 2. The optical member according to claim 1, wherein the refractive index of each layer region of the optical function layer is 1.0 or more and 2.5 or less.

3. The optical member according to claim 1 , wherein the refractive index of the optical functional layer increases from the layer region in contact with the base toward the layer region of the outermost layer of the optical functional layer.

4. The optical member according to claim 1 , wherein the refractive index of the optical functional layer decreases from the layer region in contact with the base toward the layer region of the outermost layer of the optical functional layer.

5. the optical functional layer contains one type of particle, The optical member according to claim 1 , wherein the optical functional layer has a particle content ratio different from each other in the pair of adjacent layer regions.

6. the optical functional layer contains at least two types of particles having different refractive indices, The optical member according to claim 1 , wherein the optical functional layer has a different content ratio of the at least two types of particles having different refractive indexes in the pair of adjacent layer regions.

7. The optical member according to claim 1 , wherein the particles include at least one selected from the group consisting of polymer particles, silica particles, and oxide particles.

8. 7. The optical element according to claim 6, wherein the difference between the maximum reflectance of the optical element in the visible region measured at an incident angle of 5° and the minimum reflectance of the optical element in the visible region measured at an incident angle of 5° is 5% or less.

9. The optical member according to claim 1 , wherein all of the layer regions of the optical functional layer contain the particles.

10. The optical member according to claim 1 , wherein the optical functional layer has regions with different refractive indices in a plane direction of the optical functional layer.

11. a film forming step of discharging a liquid composition containing particles onto a substrate to form a film; a film hardening step of hardening the film; an optical function layer forming step of repeating the film forming step and the film curing step to form an optical function layer having a uniform thickness; Including, a method for manufacturing an optical element, characterized in that the method includes two or more film formation steps in which the content ratio of the particles contained in the liquid composition is different such that, when the optical function layer is divided into a plurality of layer regions at intervals of 100 nm from the interface between the substrate and the optical function layer in the thickness direction of the optical function layer and divided into a plurality of layer regions, the refractive index difference between at least one pair of adjacent layer regions is greater than 0 and not greater than 0.

1.

12. the film forming step includes ejecting at least two liquid compositions having different refractive indices onto the substrate by an inkjet method to form a print pattern in a direction intersecting a thickness direction of the substrate, 12. The method for manufacturing an optical element according to claim 11, wherein forming the printing pattern comprises ejecting the liquid composition so that one liquid composition is adjacent to another liquid composition having a refractive index different from that of the one liquid composition in a direction intersecting the thickness direction of the substrate.

13. The method for manufacturing an optical member according to claim 12, wherein the printing pattern is formed by ejecting the at least two liquid compositions having different refractive indices so that the refractive index changes in at least one direction intersecting with the thickness direction of the substrate.

14. The method for manufacturing an optical member according to claim 11 , wherein the film forming step comprises discharging the at least two liquid compositions having different refractive indices while changing the discharge amounts of each of the liquid compositions.

15. The method for producing an optical member according to claim 11 , wherein the film curing step includes curing the liquid composition to a desired degree.

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